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v6.13.7
   1/*
   2 * net/tipc/link.c: TIPC link code
   3 *
   4 * Copyright (c) 1996-2007, 2012-2016, Ericsson AB
   5 * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
   6 * All rights reserved.
   7 *
   8 * Redistribution and use in source and binary forms, with or without
   9 * modification, are permitted provided that the following conditions are met:
  10 *
  11 * 1. Redistributions of source code must retain the above copyright
  12 *    notice, this list of conditions and the following disclaimer.
  13 * 2. Redistributions in binary form must reproduce the above copyright
  14 *    notice, this list of conditions and the following disclaimer in the
  15 *    documentation and/or other materials provided with the distribution.
  16 * 3. Neither the names of the copyright holders nor the names of its
  17 *    contributors may be used to endorse or promote products derived from
  18 *    this software without specific prior written permission.
  19 *
  20 * Alternatively, this software may be distributed under the terms of the
  21 * GNU General Public License ("GPL") version 2 as published by the Free
  22 * Software Foundation.
  23 *
  24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34 * POSSIBILITY OF SUCH DAMAGE.
  35 */
  36
  37#include "core.h"
  38#include "subscr.h"
  39#include "link.h"
  40#include "bcast.h"
  41#include "socket.h"
  42#include "name_distr.h"
  43#include "discover.h"
  44#include "netlink.h"
  45#include "monitor.h"
  46#include "trace.h"
  47#include "crypto.h"
  48
  49#include <linux/pkt_sched.h>
  50
  51struct tipc_stats {
  52	u32 sent_pkts;
  53	u32 recv_pkts;
  54	u32 sent_states;
  55	u32 recv_states;
  56	u32 sent_probes;
  57	u32 recv_probes;
  58	u32 sent_nacks;
  59	u32 recv_nacks;
  60	u32 sent_acks;
  61	u32 sent_bundled;
  62	u32 sent_bundles;
  63	u32 recv_bundled;
  64	u32 recv_bundles;
  65	u32 retransmitted;
  66	u32 sent_fragmented;
  67	u32 sent_fragments;
  68	u32 recv_fragmented;
  69	u32 recv_fragments;
  70	u32 link_congs;		/* # port sends blocked by congestion */
  71	u32 deferred_recv;
  72	u32 duplicates;
  73	u32 max_queue_sz;	/* send queue size high water mark */
  74	u32 accu_queue_sz;	/* used for send queue size profiling */
  75	u32 queue_sz_counts;	/* used for send queue size profiling */
  76	u32 msg_length_counts;	/* used for message length profiling */
  77	u32 msg_lengths_total;	/* used for message length profiling */
  78	u32 msg_length_profile[7]; /* used for msg. length profiling */
  79};
  80
  81/**
  82 * struct tipc_link - TIPC link data structure
  83 * @addr: network address of link's peer node
  84 * @name: link name character string
  85 * @net: pointer to namespace struct
  86 * @peer_session: link session # being used by peer end of link
  87 * @peer_bearer_id: bearer id used by link's peer endpoint
  88 * @bearer_id: local bearer id used by link
  89 * @tolerance: minimum link continuity loss needed to reset link [in ms]
  90 * @abort_limit: # of unacknowledged continuity probes needed to reset link
  91 * @state: current state of link FSM
  92 * @peer_caps: bitmap describing capabilities of peer node
  93 * @silent_intv_cnt: # of timer intervals without any reception from peer
  94 * @priority: current link priority
  95 * @net_plane: current link network plane ('A' through 'H')
  96 * @mon_state: cookie with information needed by link monitor
  97 * @mtu: current maximum packet size for this link
  98 * @advertised_mtu: advertised own mtu when link is being established
  99 * @backlogq: queue for messages waiting to be sent
 100 * @ackers: # of peers that needs to ack each packet before it can be released
 101 * @acked: # last packet acked by a certain peer. Used for broadcast.
 102 * @rcv_nxt: next sequence number to expect for inbound messages
 103 * @inputq: buffer queue for messages to be delivered upwards
 104 * @namedq: buffer queue for name table messages to be delivered upwards
 105 * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
 106 * @reasm_buf: head of partially reassembled inbound message fragments
 107 * @stats: collects statistics regarding link activity
 108 * @session: session to be used by link
 109 * @snd_nxt_state: next send seq number
 110 * @rcv_nxt_state: next rcv seq number
 111 * @in_session: have received ACTIVATE_MSG from peer
 112 * @active: link is active
 113 * @if_name: associated interface name
 114 * @rst_cnt: link reset counter
 115 * @drop_point: seq number for failover handling (FIXME)
 116 * @failover_reasm_skb: saved failover msg ptr (FIXME)
 117 * @failover_deferdq: deferred message queue for failover processing (FIXME)
 118 * @transmq: the link's transmit queue
 119 * @backlog: link's backlog by priority (importance)
 120 * @snd_nxt: next sequence number to be used
 121 * @rcv_unacked: # messages read by user, but not yet acked back to peer
 122 * @deferdq: deferred receive queue
 123 * @window: sliding window size for congestion handling
 124 * @min_win: minimal send window to be used by link
 125 * @ssthresh: slow start threshold for congestion handling
 126 * @max_win: maximal send window to be used by link
 127 * @cong_acks: congestion acks for congestion avoidance (FIXME)
 128 * @checkpoint: seq number for congestion window size handling
 129 * @reasm_tnlmsg: fragmentation/reassembly area for tunnel protocol message
 130 * @last_gap: last gap ack blocks for bcast (FIXME)
 131 * @last_ga: ptr to gap ack blocks
 132 * @bc_rcvlink: the peer specific link used for broadcast reception
 133 * @bc_sndlink: the namespace global link used for broadcast sending
 134 * @nack_state: bcast nack state
 135 * @bc_peer_is_up: peer has acked the bcast init msg
 136 */
 137struct tipc_link {
 138	u32 addr;
 139	char name[TIPC_MAX_LINK_NAME];
 140	struct net *net;
 141
 142	/* Management and link supervision data */
 143	u16 peer_session;
 144	u16 session;
 145	u16 snd_nxt_state;
 146	u16 rcv_nxt_state;
 147	u32 peer_bearer_id;
 148	u32 bearer_id;
 149	u32 tolerance;
 150	u32 abort_limit;
 151	u32 state;
 152	u16 peer_caps;
 153	bool in_session;
 154	bool active;
 155	u32 silent_intv_cnt;
 156	char if_name[TIPC_MAX_IF_NAME];
 157	u32 priority;
 158	char net_plane;
 159	struct tipc_mon_state mon_state;
 160	u16 rst_cnt;
 161
 162	/* Failover/synch */
 163	u16 drop_point;
 164	struct sk_buff *failover_reasm_skb;
 165	struct sk_buff_head failover_deferdq;
 166
 167	/* Max packet negotiation */
 168	u16 mtu;
 169	u16 advertised_mtu;
 170
 171	/* Sending */
 172	struct sk_buff_head transmq;
 173	struct sk_buff_head backlogq;
 174	struct {
 175		u16 len;
 176		u16 limit;
 177		struct sk_buff *target_bskb;
 178	} backlog[5];
 179	u16 snd_nxt;
 180
 181	/* Reception */
 182	u16 rcv_nxt;
 183	u32 rcv_unacked;
 184	struct sk_buff_head deferdq;
 185	struct sk_buff_head *inputq;
 186	struct sk_buff_head *namedq;
 187
 188	/* Congestion handling */
 189	struct sk_buff_head wakeupq;
 190	u16 window;
 191	u16 min_win;
 192	u16 ssthresh;
 193	u16 max_win;
 194	u16 cong_acks;
 195	u16 checkpoint;
 196
 197	/* Fragmentation/reassembly */
 198	struct sk_buff *reasm_buf;
 199	struct sk_buff *reasm_tnlmsg;
 200
 201	/* Broadcast */
 202	u16 ackers;
 203	u16 acked;
 204	u16 last_gap;
 205	struct tipc_gap_ack_blks *last_ga;
 206	struct tipc_link *bc_rcvlink;
 207	struct tipc_link *bc_sndlink;
 208	u8 nack_state;
 209	bool bc_peer_is_up;
 210
 211	/* Statistics */
 212	struct tipc_stats stats;
 213};
 214
 215/*
 216 * Error message prefixes
 217 */
 218static const char *link_co_err = "Link tunneling error, ";
 219static const char *link_rst_msg = "Resetting link ";
 220
 221/* Send states for broadcast NACKs
 222 */
 223enum {
 224	BC_NACK_SND_CONDITIONAL,
 225	BC_NACK_SND_UNCONDITIONAL,
 226	BC_NACK_SND_SUPPRESS,
 227};
 228
 229#define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
 230#define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))
 231
 232/* Link FSM states:
 233 */
 234enum {
 235	LINK_ESTABLISHED     = 0xe,
 236	LINK_ESTABLISHING    = 0xe  << 4,
 237	LINK_RESET           = 0x1  << 8,
 238	LINK_RESETTING       = 0x2  << 12,
 239	LINK_PEER_RESET      = 0xd  << 16,
 240	LINK_FAILINGOVER     = 0xf  << 20,
 241	LINK_SYNCHING        = 0xc  << 24
 242};
 243
 
 
 
 
 
 
 
 244static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 245			       struct sk_buff_head *xmitq);
 246static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 247				      bool probe_reply, u16 rcvgap,
 248				      int tolerance, int priority,
 249				      struct sk_buff_head *xmitq);
 250static void link_print(struct tipc_link *l, const char *str);
 251static int tipc_link_build_nack_msg(struct tipc_link *l,
 252				    struct sk_buff_head *xmitq);
 253static void tipc_link_build_bc_init_msg(struct tipc_link *l,
 254					struct sk_buff_head *xmitq);
 255static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
 256				    struct tipc_link *l, u8 start_index);
 257static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr);
 258static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
 259				     u16 acked, u16 gap,
 260				     struct tipc_gap_ack_blks *ga,
 261				     struct sk_buff_head *xmitq,
 262				     bool *retransmitted, int *rc);
 263static void tipc_link_update_cwin(struct tipc_link *l, int released,
 264				  bool retransmitted);
 265/*
 266 *  Simple non-static link routines (i.e. referenced outside this file)
 267 */
 268bool tipc_link_is_up(struct tipc_link *l)
 269{
 270	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
 271}
 272
 273bool tipc_link_peer_is_down(struct tipc_link *l)
 274{
 275	return l->state == LINK_PEER_RESET;
 276}
 277
 278bool tipc_link_is_reset(struct tipc_link *l)
 279{
 280	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 281}
 282
 283bool tipc_link_is_establishing(struct tipc_link *l)
 284{
 285	return l->state == LINK_ESTABLISHING;
 286}
 287
 288bool tipc_link_is_synching(struct tipc_link *l)
 289{
 290	return l->state == LINK_SYNCHING;
 291}
 292
 293bool tipc_link_is_failingover(struct tipc_link *l)
 294{
 295	return l->state == LINK_FAILINGOVER;
 296}
 297
 298bool tipc_link_is_blocked(struct tipc_link *l)
 299{
 300	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
 301}
 302
 303static bool link_is_bc_sndlink(struct tipc_link *l)
 304{
 305	return !l->bc_sndlink;
 306}
 307
 308static bool link_is_bc_rcvlink(struct tipc_link *l)
 309{
 310	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
 311}
 312
 313void tipc_link_set_active(struct tipc_link *l, bool active)
 314{
 315	l->active = active;
 316}
 317
 318u32 tipc_link_id(struct tipc_link *l)
 319{
 320	return l->peer_bearer_id << 16 | l->bearer_id;
 321}
 322
 323int tipc_link_min_win(struct tipc_link *l)
 324{
 325	return l->min_win;
 326}
 327
 328int tipc_link_max_win(struct tipc_link *l)
 329{
 330	return l->max_win;
 331}
 332
 333int tipc_link_prio(struct tipc_link *l)
 334{
 335	return l->priority;
 336}
 337
 338unsigned long tipc_link_tolerance(struct tipc_link *l)
 339{
 340	return l->tolerance;
 341}
 342
 343struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
 344{
 345	return l->inputq;
 346}
 347
 348char tipc_link_plane(struct tipc_link *l)
 349{
 350	return l->net_plane;
 351}
 352
 353struct net *tipc_link_net(struct tipc_link *l)
 354{
 355	return l->net;
 356}
 357
 358void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
 359{
 360	l->peer_caps = capabilities;
 361}
 362
 363void tipc_link_add_bc_peer(struct tipc_link *snd_l,
 364			   struct tipc_link *uc_l,
 365			   struct sk_buff_head *xmitq)
 366{
 367	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
 368
 369	snd_l->ackers++;
 370	rcv_l->acked = snd_l->snd_nxt - 1;
 371	snd_l->state = LINK_ESTABLISHED;
 372	tipc_link_build_bc_init_msg(uc_l, xmitq);
 373}
 374
 375void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
 376			      struct tipc_link *rcv_l,
 377			      struct sk_buff_head *xmitq)
 378{
 379	u16 ack = snd_l->snd_nxt - 1;
 380
 381	snd_l->ackers--;
 382	rcv_l->bc_peer_is_up = true;
 383	rcv_l->state = LINK_ESTABLISHED;
 384	tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
 385	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
 386	tipc_link_reset(rcv_l);
 387	rcv_l->state = LINK_RESET;
 388	if (!snd_l->ackers) {
 389		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
 390		tipc_link_reset(snd_l);
 391		snd_l->state = LINK_RESET;
 392		__skb_queue_purge(xmitq);
 393	}
 394}
 395
 396int tipc_link_bc_peers(struct tipc_link *l)
 397{
 398	return l->ackers;
 399}
 400
 401static u16 link_bc_rcv_gap(struct tipc_link *l)
 402{
 403	struct sk_buff *skb = skb_peek(&l->deferdq);
 404	u16 gap = 0;
 405
 406	if (more(l->snd_nxt, l->rcv_nxt))
 407		gap = l->snd_nxt - l->rcv_nxt;
 408	if (skb)
 409		gap = buf_seqno(skb) - l->rcv_nxt;
 410	return gap;
 411}
 412
 413void tipc_link_set_mtu(struct tipc_link *l, int mtu)
 414{
 415	l->mtu = mtu;
 416}
 417
 418int tipc_link_mtu(struct tipc_link *l)
 419{
 420	return l->mtu;
 421}
 422
 423int tipc_link_mss(struct tipc_link *l)
 424{
 425#ifdef CONFIG_TIPC_CRYPTO
 426	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
 427#else
 428	return l->mtu - INT_H_SIZE;
 429#endif
 430}
 431
 432u16 tipc_link_rcv_nxt(struct tipc_link *l)
 433{
 434	return l->rcv_nxt;
 435}
 436
 437u16 tipc_link_acked(struct tipc_link *l)
 438{
 439	return l->acked;
 440}
 441
 442char *tipc_link_name(struct tipc_link *l)
 443{
 444	return l->name;
 445}
 446
 447u32 tipc_link_state(struct tipc_link *l)
 448{
 449	return l->state;
 450}
 451
 452/**
 453 * tipc_link_create - create a new link
 454 * @net: pointer to associated network namespace
 455 * @if_name: associated interface name
 456 * @bearer_id: id (index) of associated bearer
 457 * @tolerance: link tolerance to be used by link
 458 * @net_plane: network plane (A,B,c..) this link belongs to
 459 * @mtu: mtu to be advertised by link
 460 * @priority: priority to be used by link
 461 * @min_win: minimal send window to be used by link
 462 * @max_win: maximal send window to be used by link
 463 * @session: session to be used by link
 464 * @peer: node id of peer node
 465 * @peer_caps: bitmap describing peer node capabilities
 466 * @bc_sndlink: the namespace global link used for broadcast sending
 467 * @bc_rcvlink: the peer specific link used for broadcast reception
 468 * @inputq: queue to put messages ready for delivery
 469 * @namedq: queue to put binding table update messages ready for delivery
 470 * @link: return value, pointer to put the created link
 471 * @self: local unicast link id
 472 * @peer_id: 128-bit ID of peer
 473 *
 474 * Return: true if link was created, otherwise false
 475 */
 476bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
 477		      int tolerance, char net_plane, u32 mtu, int priority,
 478		      u32 min_win, u32 max_win, u32 session, u32 self,
 479		      u32 peer, u8 *peer_id, u16 peer_caps,
 480		      struct tipc_link *bc_sndlink,
 481		      struct tipc_link *bc_rcvlink,
 482		      struct sk_buff_head *inputq,
 483		      struct sk_buff_head *namedq,
 484		      struct tipc_link **link)
 485{
 486	char peer_str[NODE_ID_STR_LEN] = {0,};
 487	char self_str[NODE_ID_STR_LEN] = {0,};
 488	struct tipc_link *l;
 489
 490	l = kzalloc(sizeof(*l), GFP_ATOMIC);
 491	if (!l)
 492		return false;
 493	*link = l;
 494	l->session = session;
 495
 496	/* Set link name for unicast links only */
 497	if (peer_id) {
 498		tipc_nodeid2string(self_str, tipc_own_id(net));
 499		if (strlen(self_str) > 16)
 500			sprintf(self_str, "%x", self);
 501		tipc_nodeid2string(peer_str, peer_id);
 502		if (strlen(peer_str) > 16)
 503			sprintf(peer_str, "%x", peer);
 504	}
 505	/* Peer i/f name will be completed by reset/activate message */
 506	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
 507		 self_str, if_name, peer_str);
 508
 509	strcpy(l->if_name, if_name);
 510	l->addr = peer;
 511	l->peer_caps = peer_caps;
 512	l->net = net;
 513	l->in_session = false;
 514	l->bearer_id = bearer_id;
 515	l->tolerance = tolerance;
 516	if (bc_rcvlink)
 517		bc_rcvlink->tolerance = tolerance;
 518	l->net_plane = net_plane;
 519	l->advertised_mtu = mtu;
 520	l->mtu = mtu;
 521	l->priority = priority;
 522	tipc_link_set_queue_limits(l, min_win, max_win);
 523	l->ackers = 1;
 524	l->bc_sndlink = bc_sndlink;
 525	l->bc_rcvlink = bc_rcvlink;
 526	l->inputq = inputq;
 527	l->namedq = namedq;
 528	l->state = LINK_RESETTING;
 529	__skb_queue_head_init(&l->transmq);
 530	__skb_queue_head_init(&l->backlogq);
 531	__skb_queue_head_init(&l->deferdq);
 532	__skb_queue_head_init(&l->failover_deferdq);
 533	skb_queue_head_init(&l->wakeupq);
 534	skb_queue_head_init(l->inputq);
 535	return true;
 536}
 537
 538/**
 539 * tipc_link_bc_create - create new link to be used for broadcast
 540 * @net: pointer to associated network namespace
 541 * @mtu: mtu to be used initially if no peers
 542 * @min_win: minimal send window to be used by link
 543 * @max_win: maximal send window to be used by link
 544 * @inputq: queue to put messages ready for delivery
 545 * @namedq: queue to put binding table update messages ready for delivery
 546 * @link: return value, pointer to put the created link
 547 * @ownnode: identity of own node
 548 * @peer: node id of peer node
 549 * @peer_id: 128-bit ID of peer
 550 * @peer_caps: bitmap describing peer node capabilities
 551 * @bc_sndlink: the namespace global link used for broadcast sending
 552 *
 553 * Return: true if link was created, otherwise false
 554 */
 555bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
 556			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
 557			 struct sk_buff_head *inputq,
 558			 struct sk_buff_head *namedq,
 559			 struct tipc_link *bc_sndlink,
 560			 struct tipc_link **link)
 561{
 562	struct tipc_link *l;
 563
 564	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
 565			      max_win, 0, ownnode, peer, NULL, peer_caps,
 566			      bc_sndlink, NULL, inputq, namedq, link))
 567		return false;
 568
 569	l = *link;
 570	if (peer_id) {
 571		char peer_str[NODE_ID_STR_LEN] = {0,};
 572
 573		tipc_nodeid2string(peer_str, peer_id);
 574		if (strlen(peer_str) > 16)
 575			sprintf(peer_str, "%x", peer);
 576		/* Broadcast receiver link name: "broadcast-link:<peer>" */
 577		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
 578			 peer_str);
 579	} else {
 580		strcpy(l->name, tipc_bclink_name);
 581	}
 582	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
 583	tipc_link_reset(l);
 584	l->state = LINK_RESET;
 585	l->ackers = 0;
 586	l->bc_rcvlink = l;
 587
 588	/* Broadcast send link is always up */
 589	if (link_is_bc_sndlink(l))
 590		l->state = LINK_ESTABLISHED;
 591
 592	/* Disable replicast if even a single peer doesn't support it */
 593	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
 594		tipc_bcast_toggle_rcast(net, false);
 595
 596	return true;
 597}
 598
 599/**
 600 * tipc_link_fsm_evt - link finite state machine
 601 * @l: pointer to link
 602 * @evt: state machine event to be processed
 603 */
 604int tipc_link_fsm_evt(struct tipc_link *l, int evt)
 605{
 606	int rc = 0;
 607	int old_state = l->state;
 608
 609	switch (l->state) {
 610	case LINK_RESETTING:
 611		switch (evt) {
 612		case LINK_PEER_RESET_EVT:
 613			l->state = LINK_PEER_RESET;
 614			break;
 615		case LINK_RESET_EVT:
 616			l->state = LINK_RESET;
 617			break;
 618		case LINK_FAILURE_EVT:
 619		case LINK_FAILOVER_BEGIN_EVT:
 620		case LINK_ESTABLISH_EVT:
 621		case LINK_FAILOVER_END_EVT:
 622		case LINK_SYNCH_BEGIN_EVT:
 623		case LINK_SYNCH_END_EVT:
 624		default:
 625			goto illegal_evt;
 626		}
 627		break;
 628	case LINK_RESET:
 629		switch (evt) {
 630		case LINK_PEER_RESET_EVT:
 631			l->state = LINK_ESTABLISHING;
 632			break;
 633		case LINK_FAILOVER_BEGIN_EVT:
 634			l->state = LINK_FAILINGOVER;
 635			break;
 636		case LINK_FAILURE_EVT:
 637		case LINK_RESET_EVT:
 638		case LINK_ESTABLISH_EVT:
 639		case LINK_FAILOVER_END_EVT:
 640			break;
 641		case LINK_SYNCH_BEGIN_EVT:
 642		case LINK_SYNCH_END_EVT:
 643		default:
 644			goto illegal_evt;
 645		}
 646		break;
 647	case LINK_PEER_RESET:
 648		switch (evt) {
 649		case LINK_RESET_EVT:
 650			l->state = LINK_ESTABLISHING;
 651			break;
 652		case LINK_PEER_RESET_EVT:
 653		case LINK_ESTABLISH_EVT:
 654		case LINK_FAILURE_EVT:
 655			break;
 656		case LINK_SYNCH_BEGIN_EVT:
 657		case LINK_SYNCH_END_EVT:
 658		case LINK_FAILOVER_BEGIN_EVT:
 659		case LINK_FAILOVER_END_EVT:
 660		default:
 661			goto illegal_evt;
 662		}
 663		break;
 664	case LINK_FAILINGOVER:
 665		switch (evt) {
 666		case LINK_FAILOVER_END_EVT:
 667			l->state = LINK_RESET;
 668			break;
 669		case LINK_PEER_RESET_EVT:
 670		case LINK_RESET_EVT:
 671		case LINK_ESTABLISH_EVT:
 672		case LINK_FAILURE_EVT:
 673			break;
 674		case LINK_FAILOVER_BEGIN_EVT:
 675		case LINK_SYNCH_BEGIN_EVT:
 676		case LINK_SYNCH_END_EVT:
 677		default:
 678			goto illegal_evt;
 679		}
 680		break;
 681	case LINK_ESTABLISHING:
 682		switch (evt) {
 683		case LINK_ESTABLISH_EVT:
 684			l->state = LINK_ESTABLISHED;
 685			break;
 686		case LINK_FAILOVER_BEGIN_EVT:
 687			l->state = LINK_FAILINGOVER;
 688			break;
 689		case LINK_RESET_EVT:
 690			l->state = LINK_RESET;
 691			break;
 692		case LINK_FAILURE_EVT:
 693		case LINK_PEER_RESET_EVT:
 694		case LINK_SYNCH_BEGIN_EVT:
 695		case LINK_FAILOVER_END_EVT:
 696			break;
 697		case LINK_SYNCH_END_EVT:
 698		default:
 699			goto illegal_evt;
 700		}
 701		break;
 702	case LINK_ESTABLISHED:
 703		switch (evt) {
 704		case LINK_PEER_RESET_EVT:
 705			l->state = LINK_PEER_RESET;
 706			rc |= TIPC_LINK_DOWN_EVT;
 707			break;
 708		case LINK_FAILURE_EVT:
 709			l->state = LINK_RESETTING;
 710			rc |= TIPC_LINK_DOWN_EVT;
 711			break;
 712		case LINK_RESET_EVT:
 713			l->state = LINK_RESET;
 714			break;
 715		case LINK_ESTABLISH_EVT:
 716		case LINK_SYNCH_END_EVT:
 717			break;
 718		case LINK_SYNCH_BEGIN_EVT:
 719			l->state = LINK_SYNCHING;
 720			break;
 721		case LINK_FAILOVER_BEGIN_EVT:
 722		case LINK_FAILOVER_END_EVT:
 723		default:
 724			goto illegal_evt;
 725		}
 726		break;
 727	case LINK_SYNCHING:
 728		switch (evt) {
 729		case LINK_PEER_RESET_EVT:
 730			l->state = LINK_PEER_RESET;
 731			rc |= TIPC_LINK_DOWN_EVT;
 732			break;
 733		case LINK_FAILURE_EVT:
 734			l->state = LINK_RESETTING;
 735			rc |= TIPC_LINK_DOWN_EVT;
 736			break;
 737		case LINK_RESET_EVT:
 738			l->state = LINK_RESET;
 739			break;
 740		case LINK_ESTABLISH_EVT:
 741		case LINK_SYNCH_BEGIN_EVT:
 742			break;
 743		case LINK_SYNCH_END_EVT:
 744			l->state = LINK_ESTABLISHED;
 745			break;
 746		case LINK_FAILOVER_BEGIN_EVT:
 747		case LINK_FAILOVER_END_EVT:
 748		default:
 749			goto illegal_evt;
 750		}
 751		break;
 752	default:
 753		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
 754	}
 755	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
 756	return rc;
 757illegal_evt:
 758	pr_err("Illegal FSM event %x in state %x on link %s\n",
 759	       evt, l->state, l->name);
 760	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
 761	return rc;
 762}
 763
 764/* link_profile_stats - update statistical profiling of traffic
 765 */
 766static void link_profile_stats(struct tipc_link *l)
 767{
 768	struct sk_buff *skb;
 769	struct tipc_msg *msg;
 770	int length;
 771
 772	/* Update counters used in statistical profiling of send traffic */
 773	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 774	l->stats.queue_sz_counts++;
 775
 776	skb = skb_peek(&l->transmq);
 777	if (!skb)
 778		return;
 779	msg = buf_msg(skb);
 780	length = msg_size(msg);
 781
 782	if (msg_user(msg) == MSG_FRAGMENTER) {
 783		if (msg_type(msg) != FIRST_FRAGMENT)
 784			return;
 785		length = msg_size(msg_inner_hdr(msg));
 786	}
 787	l->stats.msg_lengths_total += length;
 788	l->stats.msg_length_counts++;
 789	if (length <= 64)
 790		l->stats.msg_length_profile[0]++;
 791	else if (length <= 256)
 792		l->stats.msg_length_profile[1]++;
 793	else if (length <= 1024)
 794		l->stats.msg_length_profile[2]++;
 795	else if (length <= 4096)
 796		l->stats.msg_length_profile[3]++;
 797	else if (length <= 16384)
 798		l->stats.msg_length_profile[4]++;
 799	else if (length <= 32768)
 800		l->stats.msg_length_profile[5]++;
 801	else
 802		l->stats.msg_length_profile[6]++;
 803}
 804
 805/**
 806 * tipc_link_too_silent - check if link is "too silent"
 807 * @l: tipc link to be checked
 808 *
 809 * Return: true if the link 'silent_intv_cnt' is about to reach the
 810 * 'abort_limit' value, otherwise false
 811 */
 812bool tipc_link_too_silent(struct tipc_link *l)
 813{
 814	return (l->silent_intv_cnt + 2 > l->abort_limit);
 815}
 816
 817/* tipc_link_timeout - perform periodic task as instructed from node timeout
 818 */
 819int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 820{
 821	int mtyp = 0;
 822	int rc = 0;
 823	bool state = false;
 824	bool probe = false;
 825	bool setup = false;
 826	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
 827	u16 bc_acked = l->bc_rcvlink->acked;
 828	struct tipc_mon_state *mstate = &l->mon_state;
 829
 830	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
 831	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
 832	switch (l->state) {
 833	case LINK_ESTABLISHED:
 834	case LINK_SYNCHING:
 835		mtyp = STATE_MSG;
 836		link_profile_stats(l);
 837		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
 838		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
 839			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 840		state = bc_acked != bc_snt;
 841		state |= l->bc_rcvlink->rcv_unacked;
 842		state |= l->rcv_unacked;
 843		state |= !skb_queue_empty(&l->transmq);
 844		probe = mstate->probing;
 845		probe |= l->silent_intv_cnt;
 846		if (probe || mstate->monitoring)
 847			l->silent_intv_cnt++;
 848		probe |= !skb_queue_empty(&l->deferdq);
 849		if (l->snd_nxt == l->checkpoint) {
 850			tipc_link_update_cwin(l, 0, 0);
 851			probe = true;
 852		}
 853		l->checkpoint = l->snd_nxt;
 854		break;
 855	case LINK_RESET:
 856		setup = l->rst_cnt++ <= 4;
 857		setup |= !(l->rst_cnt % 16);
 858		mtyp = RESET_MSG;
 859		break;
 860	case LINK_ESTABLISHING:
 861		setup = true;
 862		mtyp = ACTIVATE_MSG;
 863		break;
 864	case LINK_PEER_RESET:
 865	case LINK_RESETTING:
 866	case LINK_FAILINGOVER:
 867		break;
 868	default:
 869		break;
 870	}
 871
 872	if (state || probe || setup)
 873		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
 874
 875	return rc;
 876}
 877
 878/**
 879 * link_schedule_user - schedule a message sender for wakeup after congestion
 880 * @l: congested link
 881 * @hdr: header of message that is being sent
 882 * Create pseudo msg to send back to user when congestion abates
 883 */
 884static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
 885{
 886	u32 dnode = tipc_own_addr(l->net);
 887	u32 dport = msg_origport(hdr);
 888	struct sk_buff *skb;
 889
 890	/* Create and schedule wakeup pseudo message */
 891	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 892			      dnode, l->addr, dport, 0, 0);
 893	if (!skb)
 894		return -ENOBUFS;
 895	msg_set_dest_droppable(buf_msg(skb), true);
 896	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
 897	skb_queue_tail(&l->wakeupq, skb);
 898	l->stats.link_congs++;
 899	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
 900	return -ELINKCONG;
 901}
 902
 903/**
 904 * link_prepare_wakeup - prepare users for wakeup after congestion
 905 * @l: congested link
 906 * Wake up a number of waiting users, as permitted by available space
 907 * in the send queue
 908 */
 909static void link_prepare_wakeup(struct tipc_link *l)
 910{
 911	struct sk_buff_head *wakeupq = &l->wakeupq;
 912	struct sk_buff_head *inputq = l->inputq;
 913	struct sk_buff *skb, *tmp;
 914	struct sk_buff_head tmpq;
 915	int avail[5] = {0,};
 916	int imp = 0;
 917
 918	__skb_queue_head_init(&tmpq);
 919
 920	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
 921		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
 922
 923	skb_queue_walk_safe(wakeupq, skb, tmp) {
 924		imp = TIPC_SKB_CB(skb)->chain_imp;
 925		if (avail[imp] <= 0)
 926			continue;
 927		avail[imp]--;
 928		__skb_unlink(skb, wakeupq);
 929		__skb_queue_tail(&tmpq, skb);
 930	}
 931
 932	spin_lock_bh(&inputq->lock);
 933	skb_queue_splice_tail(&tmpq, inputq);
 934	spin_unlock_bh(&inputq->lock);
 935
 936}
 937
 938/**
 939 * tipc_link_set_skb_retransmit_time - set the time at which retransmission of
 940 *                                     the given skb should be next attempted
 941 * @skb: skb to set a future retransmission time for
 942 * @l: link the skb will be transmitted on
 943 */
 944static void tipc_link_set_skb_retransmit_time(struct sk_buff *skb,
 945					      struct tipc_link *l)
 946{
 947	if (link_is_bc_sndlink(l))
 948		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
 949	else
 950		TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
 951}
 952
 953void tipc_link_reset(struct tipc_link *l)
 954{
 955	struct sk_buff_head list;
 956	u32 imp;
 957
 958	__skb_queue_head_init(&list);
 959
 960	l->in_session = false;
 961	/* Force re-synch of peer session number before establishing */
 962	l->peer_session--;
 963	l->session++;
 964	l->mtu = l->advertised_mtu;
 965
 966	spin_lock_bh(&l->wakeupq.lock);
 967	skb_queue_splice_init(&l->wakeupq, &list);
 968	spin_unlock_bh(&l->wakeupq.lock);
 969
 970	spin_lock_bh(&l->inputq->lock);
 971	skb_queue_splice_init(&list, l->inputq);
 972	spin_unlock_bh(&l->inputq->lock);
 973
 974	__skb_queue_purge(&l->transmq);
 975	__skb_queue_purge(&l->deferdq);
 976	__skb_queue_purge(&l->backlogq);
 977	__skb_queue_purge(&l->failover_deferdq);
 978	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
 979		l->backlog[imp].len = 0;
 980		l->backlog[imp].target_bskb = NULL;
 981	}
 982	kfree_skb(l->reasm_buf);
 983	kfree_skb(l->reasm_tnlmsg);
 984	kfree_skb(l->failover_reasm_skb);
 985	l->reasm_buf = NULL;
 986	l->reasm_tnlmsg = NULL;
 987	l->failover_reasm_skb = NULL;
 988	l->rcv_unacked = 0;
 989	l->snd_nxt = 1;
 990	l->rcv_nxt = 1;
 991	l->snd_nxt_state = 1;
 992	l->rcv_nxt_state = 1;
 993	l->acked = 0;
 994	l->last_gap = 0;
 995	kfree(l->last_ga);
 996	l->last_ga = NULL;
 997	l->silent_intv_cnt = 0;
 998	l->rst_cnt = 0;
 999	l->bc_peer_is_up = false;
1000	memset(&l->mon_state, 0, sizeof(l->mon_state));
1001	tipc_link_reset_stats(l);
1002}
1003
1004/**
1005 * tipc_link_xmit(): enqueue buffer list according to queue situation
1006 * @l: link to use
1007 * @list: chain of buffers containing message
1008 * @xmitq: returned list of packets to be sent by caller
1009 *
1010 * Consumes the buffer chain.
1011 * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
1012 * Return: 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
1013 */
1014int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
1015		   struct sk_buff_head *xmitq)
1016{
1017	struct sk_buff_head *backlogq = &l->backlogq;
1018	struct sk_buff_head *transmq = &l->transmq;
1019	struct sk_buff *skb, *_skb;
1020	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1021	u16 ack = l->rcv_nxt - 1;
1022	u16 seqno = l->snd_nxt;
1023	int pkt_cnt = skb_queue_len(list);
1024	unsigned int mss = tipc_link_mss(l);
1025	unsigned int cwin = l->window;
1026	unsigned int mtu = l->mtu;
1027	struct tipc_msg *hdr;
1028	bool new_bundle;
1029	int rc = 0;
1030	int imp;
1031
1032	if (pkt_cnt <= 0)
1033		return 0;
1034
1035	hdr = buf_msg(skb_peek(list));
1036	if (unlikely(msg_size(hdr) > mtu)) {
1037		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1038			skb_queue_len(list), msg_user(hdr),
1039			msg_type(hdr), msg_size(hdr), mtu);
1040		__skb_queue_purge(list);
1041		return -EMSGSIZE;
1042	}
1043
1044	imp = msg_importance(hdr);
1045	/* Allow oversubscription of one data msg per source at congestion */
1046	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1047		if (imp == TIPC_SYSTEM_IMPORTANCE) {
1048			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1049			return -ENOBUFS;
1050		}
1051		rc = link_schedule_user(l, hdr);
1052	}
1053
1054	if (pkt_cnt > 1) {
1055		l->stats.sent_fragmented++;
1056		l->stats.sent_fragments += pkt_cnt;
1057	}
1058
1059	/* Prepare each packet for sending, and add to relevant queue: */
1060	while ((skb = __skb_dequeue(list))) {
1061		if (likely(skb_queue_len(transmq) < cwin)) {
1062			hdr = buf_msg(skb);
1063			msg_set_seqno(hdr, seqno);
1064			msg_set_ack(hdr, ack);
1065			msg_set_bcast_ack(hdr, bc_ack);
1066			_skb = skb_clone(skb, GFP_ATOMIC);
1067			if (!_skb) {
1068				kfree_skb(skb);
1069				__skb_queue_purge(list);
1070				return -ENOBUFS;
1071			}
1072			__skb_queue_tail(transmq, skb);
1073			tipc_link_set_skb_retransmit_time(skb, l);
1074			__skb_queue_tail(xmitq, _skb);
1075			TIPC_SKB_CB(skb)->ackers = l->ackers;
1076			l->rcv_unacked = 0;
1077			l->stats.sent_pkts++;
1078			seqno++;
1079			continue;
1080		}
1081		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1082					mss, l->addr, &new_bundle)) {
1083			if (skb) {
1084				/* Keep a ref. to the skb for next try */
1085				l->backlog[imp].target_bskb = skb;
1086				l->backlog[imp].len++;
1087				__skb_queue_tail(backlogq, skb);
1088			} else {
1089				if (new_bundle) {
1090					l->stats.sent_bundles++;
1091					l->stats.sent_bundled++;
1092				}
1093				l->stats.sent_bundled++;
1094			}
1095			continue;
1096		}
1097		l->backlog[imp].target_bskb = NULL;
1098		l->backlog[imp].len += (1 + skb_queue_len(list));
1099		__skb_queue_tail(backlogq, skb);
1100		skb_queue_splice_tail_init(list, backlogq);
1101	}
1102	l->snd_nxt = seqno;
1103	return rc;
1104}
1105
1106static void tipc_link_update_cwin(struct tipc_link *l, int released,
1107				  bool retransmitted)
1108{
1109	int bklog_len = skb_queue_len(&l->backlogq);
1110	struct sk_buff_head *txq = &l->transmq;
1111	int txq_len = skb_queue_len(txq);
1112	u16 cwin = l->window;
1113
1114	/* Enter fast recovery */
1115	if (unlikely(retransmitted)) {
1116		l->ssthresh = max_t(u16, l->window / 2, 300);
1117		l->window = min_t(u16, l->ssthresh, l->window);
1118		return;
1119	}
1120	/* Enter slow start */
1121	if (unlikely(!released)) {
1122		l->ssthresh = max_t(u16, l->window / 2, 300);
1123		l->window = l->min_win;
1124		return;
1125	}
1126	/* Don't increase window if no pressure on the transmit queue */
1127	if (txq_len + bklog_len < cwin)
1128		return;
1129
1130	/* Don't increase window if there are holes the transmit queue */
1131	if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1132		return;
1133
1134	l->cong_acks += released;
1135
1136	/* Slow start  */
1137	if (cwin <= l->ssthresh) {
1138		l->window = min_t(u16, cwin + released, l->max_win);
1139		return;
1140	}
1141	/* Congestion avoidance */
1142	if (l->cong_acks < cwin)
1143		return;
1144	l->window = min_t(u16, ++cwin, l->max_win);
1145	l->cong_acks = 0;
1146}
1147
1148static void tipc_link_advance_backlog(struct tipc_link *l,
1149				      struct sk_buff_head *xmitq)
1150{
1151	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1152	struct sk_buff_head *txq = &l->transmq;
1153	struct sk_buff *skb, *_skb;
1154	u16 ack = l->rcv_nxt - 1;
1155	u16 seqno = l->snd_nxt;
1156	struct tipc_msg *hdr;
1157	u16 cwin = l->window;
1158	u32 imp;
1159
1160	while (skb_queue_len(txq) < cwin) {
1161		skb = skb_peek(&l->backlogq);
1162		if (!skb)
1163			break;
1164		_skb = skb_clone(skb, GFP_ATOMIC);
1165		if (!_skb)
1166			break;
1167		__skb_dequeue(&l->backlogq);
1168		hdr = buf_msg(skb);
1169		imp = msg_importance(hdr);
1170		l->backlog[imp].len--;
1171		if (unlikely(skb == l->backlog[imp].target_bskb))
1172			l->backlog[imp].target_bskb = NULL;
1173		__skb_queue_tail(&l->transmq, skb);
1174		tipc_link_set_skb_retransmit_time(skb, l);
1175
1176		__skb_queue_tail(xmitq, _skb);
1177		TIPC_SKB_CB(skb)->ackers = l->ackers;
1178		msg_set_seqno(hdr, seqno);
1179		msg_set_ack(hdr, ack);
1180		msg_set_bcast_ack(hdr, bc_ack);
1181		l->rcv_unacked = 0;
1182		l->stats.sent_pkts++;
1183		seqno++;
1184	}
1185	l->snd_nxt = seqno;
1186}
1187
1188/**
1189 * link_retransmit_failure() - Detect repeated retransmit failures
1190 * @l: tipc link sender
1191 * @r: tipc link receiver (= l in case of unicast)
1192 * @rc: returned code
1193 *
1194 * Return: true if the repeated retransmit failures happens, otherwise
1195 * false
1196 */
1197static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1198				    int *rc)
1199{
1200	struct sk_buff *skb = skb_peek(&l->transmq);
1201	struct tipc_msg *hdr;
1202
1203	if (!skb)
1204		return false;
1205
1206	if (!TIPC_SKB_CB(skb)->retr_cnt)
1207		return false;
1208
1209	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1210			msecs_to_jiffies(r->tolerance * 10)))
1211		return false;
1212
1213	hdr = buf_msg(skb);
1214	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1215		return false;
1216
1217	pr_warn("Retransmission failure on link <%s>\n", l->name);
1218	link_print(l, "State of link ");
1219	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1220		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1221	pr_info("sqno %u, prev: %x, dest: %x\n",
1222		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1223	pr_info("retr_stamp %d, retr_cnt %d\n",
1224		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1225		TIPC_SKB_CB(skb)->retr_cnt);
1226
1227	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1228	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1229	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1230
1231	if (link_is_bc_sndlink(l)) {
1232		r->state = LINK_RESET;
1233		*rc |= TIPC_LINK_DOWN_EVT;
1234	} else {
1235		*rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1236	}
1237
1238	return true;
1239}
1240
1241/* tipc_data_input - deliver data and name distr msgs to upper layer
1242 *
1243 * Consumes buffer if message is of right type
1244 * Node lock must be held
1245 */
1246static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1247			    struct sk_buff_head *inputq)
1248{
1249	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1250	struct tipc_msg *hdr = buf_msg(skb);
1251
1252	switch (msg_user(hdr)) {
1253	case TIPC_LOW_IMPORTANCE:
1254	case TIPC_MEDIUM_IMPORTANCE:
1255	case TIPC_HIGH_IMPORTANCE:
1256	case TIPC_CRITICAL_IMPORTANCE:
1257		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1258			skb_queue_tail(mc_inputq, skb);
1259			return true;
1260		}
1261		fallthrough;
1262	case CONN_MANAGER:
1263		skb_queue_tail(inputq, skb);
1264		return true;
1265	case GROUP_PROTOCOL:
1266		skb_queue_tail(mc_inputq, skb);
1267		return true;
1268	case NAME_DISTRIBUTOR:
1269		l->bc_rcvlink->state = LINK_ESTABLISHED;
1270		skb_queue_tail(l->namedq, skb);
1271		return true;
1272	case MSG_BUNDLER:
1273	case TUNNEL_PROTOCOL:
1274	case MSG_FRAGMENTER:
1275	case BCAST_PROTOCOL:
1276		return false;
1277#ifdef CONFIG_TIPC_CRYPTO
1278	case MSG_CRYPTO:
1279		if (sysctl_tipc_key_exchange_enabled &&
1280		    TIPC_SKB_CB(skb)->decrypted) {
1281			tipc_crypto_msg_rcv(l->net, skb);
1282			return true;
1283		}
1284		fallthrough;
1285#endif
1286	default:
1287		pr_warn("Dropping received illegal msg type\n");
1288		kfree_skb(skb);
1289		return true;
1290	}
1291}
1292
1293/* tipc_link_input - process packet that has passed link protocol check
1294 *
1295 * Consumes buffer
1296 */
1297static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1298			   struct sk_buff_head *inputq,
1299			   struct sk_buff **reasm_skb)
1300{
1301	struct tipc_msg *hdr = buf_msg(skb);
1302	struct sk_buff *iskb;
1303	struct sk_buff_head tmpq;
1304	int usr = msg_user(hdr);
1305	int pos = 0;
1306
1307	if (usr == MSG_BUNDLER) {
1308		skb_queue_head_init(&tmpq);
1309		l->stats.recv_bundles++;
1310		l->stats.recv_bundled += msg_msgcnt(hdr);
1311		while (tipc_msg_extract(skb, &iskb, &pos))
1312			tipc_data_input(l, iskb, &tmpq);
1313		tipc_skb_queue_splice_tail(&tmpq, inputq);
1314		return 0;
1315	} else if (usr == MSG_FRAGMENTER) {
1316		l->stats.recv_fragments++;
1317		if (tipc_buf_append(reasm_skb, &skb)) {
1318			l->stats.recv_fragmented++;
1319			tipc_data_input(l, skb, inputq);
1320		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1321			pr_warn_ratelimited("Unable to build fragment list\n");
1322			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1323		}
1324		return 0;
1325	} else if (usr == BCAST_PROTOCOL) {
1326		tipc_bcast_lock(l->net);
1327		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1328		tipc_bcast_unlock(l->net);
1329	}
1330
1331	kfree_skb(skb);
1332	return 0;
1333}
1334
1335/* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1336 *			 inner message along with the ones in the old link's
1337 *			 deferdq
1338 * @l: tunnel link
1339 * @skb: TUNNEL_PROTOCOL message
1340 * @inputq: queue to put messages ready for delivery
1341 */
1342static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1343			     struct sk_buff_head *inputq)
1344{
1345	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1346	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1347	struct sk_buff_head *fdefq = &l->failover_deferdq;
1348	struct tipc_msg *hdr = buf_msg(skb);
1349	struct sk_buff *iskb;
1350	int ipos = 0;
1351	int rc = 0;
1352	u16 seqno;
1353
1354	if (msg_type(hdr) == SYNCH_MSG) {
1355		kfree_skb(skb);
1356		return 0;
1357	}
1358
1359	/* Not a fragment? */
1360	if (likely(!msg_nof_fragms(hdr))) {
1361		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1362			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1363					    skb_queue_len(fdefq));
1364			return 0;
1365		}
1366		kfree_skb(skb);
1367	} else {
1368		/* Set fragment type for buf_append */
1369		if (msg_fragm_no(hdr) == 1)
1370			msg_set_type(hdr, FIRST_FRAGMENT);
1371		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1372			msg_set_type(hdr, FRAGMENT);
1373		else
1374			msg_set_type(hdr, LAST_FRAGMENT);
1375
1376		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1377			/* Successful but non-complete reassembly? */
1378			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1379				return 0;
1380			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1381			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1382		}
1383		iskb = skb;
1384	}
1385
1386	do {
1387		seqno = buf_seqno(iskb);
1388		if (unlikely(less(seqno, l->drop_point))) {
1389			kfree_skb(iskb);
1390			continue;
1391		}
1392		if (unlikely(seqno != l->drop_point)) {
1393			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
1394			continue;
1395		}
1396
1397		l->drop_point++;
1398		if (!tipc_data_input(l, iskb, inputq))
1399			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1400		if (unlikely(rc))
1401			break;
1402	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1403
1404	return rc;
1405}
1406
1407/**
1408 * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1409 * @ga: returned pointer to the Gap ACK blocks if any
1410 * @l: the tipc link
1411 * @hdr: the PROTOCOL/STATE_MSG header
1412 * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1413 *
1414 * Return: the total Gap ACK blocks size
1415 */
1416u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1417			  struct tipc_msg *hdr, bool uc)
1418{
1419	struct tipc_gap_ack_blks *p;
1420	u16 sz = 0;
1421
1422	/* Does peer support the Gap ACK blocks feature? */
1423	if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1424		p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1425		sz = ntohs(p->len);
1426		/* Sanity check */
1427		if (sz == struct_size(p, gacks, size_add(p->ugack_cnt, p->bgack_cnt))) {
1428			/* Good, check if the desired type exists */
1429			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1430				goto ok;
1431		/* Backward compatible: peer might not support bc, but uc? */
1432		} else if (uc && sz == struct_size(p, gacks, p->ugack_cnt)) {
1433			if (p->ugack_cnt) {
1434				p->bgack_cnt = 0;
1435				goto ok;
1436			}
1437		}
1438	}
1439	/* Other cases: ignore! */
1440	p = NULL;
1441
1442ok:
1443	*ga = p;
1444	return sz;
1445}
1446
1447static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1448				    struct tipc_link *l, u8 start_index)
1449{
1450	struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1451	struct sk_buff *skb = skb_peek(&l->deferdq);
1452	u16 expect, seqno = 0;
1453	u8 n = 0;
1454
1455	if (!skb)
1456		return 0;
1457
1458	expect = buf_seqno(skb);
1459	skb_queue_walk(&l->deferdq, skb) {
1460		seqno = buf_seqno(skb);
1461		if (unlikely(more(seqno, expect))) {
1462			gacks[n].ack = htons(expect - 1);
1463			gacks[n].gap = htons(seqno - expect);
1464			if (++n >= MAX_GAP_ACK_BLKS / 2) {
1465				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1466						    l->name, n,
1467						    skb_queue_len(&l->deferdq));
1468				return n;
1469			}
1470		} else if (unlikely(less(seqno, expect))) {
1471			pr_warn("Unexpected skb in deferdq!\n");
1472			continue;
1473		}
1474		expect = seqno + 1;
1475	}
1476
1477	/* last block */
1478	gacks[n].ack = htons(seqno);
1479	gacks[n].gap = 0;
1480	n++;
1481	return n;
1482}
1483
1484/* tipc_build_gap_ack_blks - build Gap ACK blocks
1485 * @l: tipc unicast link
1486 * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1487 *
1488 * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1489 * links of a certain peer, the buffer after built has the network data format
1490 * as found at the struct tipc_gap_ack_blks definition.
1491 *
1492 * returns the actual allocated memory size
1493 */
1494static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1495{
1496	struct tipc_link *bcl = l->bc_rcvlink;
1497	struct tipc_gap_ack_blks *ga;
1498	u16 len;
1499
1500	ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1501
1502	/* Start with broadcast link first */
1503	tipc_bcast_lock(bcl->net);
1504	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1505	msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1506	ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1507	tipc_bcast_unlock(bcl->net);
1508
1509	/* Now for unicast link, but an explicit NACK only (???) */
1510	ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1511			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1512
1513	/* Total len */
1514	len = struct_size(ga, gacks, size_add(ga->bgack_cnt, ga->ugack_cnt));
1515	ga->len = htons(len);
1516	return len;
1517}
1518
1519/* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1520 *			       acked packets, also doing retransmissions if
1521 *			       gaps found
1522 * @l: tipc link with transmq queue to be advanced
1523 * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1524 * @acked: seqno of last packet acked by peer without any gaps before
1525 * @gap: # of gap packets
1526 * @ga: buffer pointer to Gap ACK blocks from peer
1527 * @xmitq: queue for accumulating the retransmitted packets if any
1528 * @retransmitted: returned boolean value if a retransmission is really issued
1529 * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1530 *      happens (- unlikely case)
1531 *
1532 * Return: the number of packets released from the link transmq
1533 */
1534static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1535				     u16 acked, u16 gap,
1536				     struct tipc_gap_ack_blks *ga,
1537				     struct sk_buff_head *xmitq,
1538				     bool *retransmitted, int *rc)
1539{
1540	struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1541	struct tipc_gap_ack *gacks = NULL;
1542	struct sk_buff *skb, *_skb, *tmp;
1543	struct tipc_msg *hdr;
1544	u32 qlen = skb_queue_len(&l->transmq);
1545	u16 nacked = acked, ngap = gap, gack_cnt = 0;
1546	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1547	u16 ack = l->rcv_nxt - 1;
1548	u16 seqno, n = 0;
1549	u16 end = r->acked, start = end, offset = r->last_gap;
1550	u16 si = (last_ga) ? last_ga->start_index : 0;
1551	bool is_uc = !link_is_bc_sndlink(l);
1552	bool bc_has_acked = false;
1553
1554	trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1555
1556	/* Determine Gap ACK blocks if any for the particular link */
1557	if (ga && is_uc) {
1558		/* Get the Gap ACKs, uc part */
1559		gack_cnt = ga->ugack_cnt;
1560		gacks = &ga->gacks[ga->bgack_cnt];
1561	} else if (ga) {
1562		/* Copy the Gap ACKs, bc part, for later renewal if needed */
1563		this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),
1564				  GFP_ATOMIC);
1565		if (likely(this_ga)) {
1566			this_ga->start_index = 0;
1567			/* Start with the bc Gap ACKs */
1568			gack_cnt = this_ga->bgack_cnt;
1569			gacks = &this_ga->gacks[0];
1570		} else {
1571			/* Hmm, we can get in trouble..., simply ignore it */
1572			pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1573		}
1574	}
1575
1576	/* Advance the link transmq */
1577	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1578		seqno = buf_seqno(skb);
1579
1580next_gap_ack:
1581		if (less_eq(seqno, nacked)) {
1582			if (is_uc)
1583				goto release;
1584			/* Skip packets peer has already acked */
1585			if (!more(seqno, r->acked))
1586				continue;
1587			/* Get the next of last Gap ACK blocks */
1588			while (more(seqno, end)) {
1589				if (!last_ga || si >= last_ga->bgack_cnt)
1590					break;
1591				start = end + offset + 1;
1592				end = ntohs(last_ga->gacks[si].ack);
1593				offset = ntohs(last_ga->gacks[si].gap);
1594				si++;
1595				WARN_ONCE(more(start, end) ||
1596					  (!offset &&
1597					   si < last_ga->bgack_cnt) ||
1598					  si > MAX_GAP_ACK_BLKS,
1599					  "Corrupted Gap ACK: %d %d %d %d %d\n",
1600					  start, end, offset, si,
1601					  last_ga->bgack_cnt);
1602			}
1603			/* Check against the last Gap ACK block */
1604			if (tipc_in_range(seqno, start, end))
1605				continue;
1606			/* Update/release the packet peer is acking */
1607			bc_has_acked = true;
1608			if (--TIPC_SKB_CB(skb)->ackers)
1609				continue;
1610release:
1611			/* release skb */
1612			__skb_unlink(skb, &l->transmq);
1613			kfree_skb(skb);
1614		} else if (less_eq(seqno, nacked + ngap)) {
1615			/* First gap: check if repeated retrans failures? */
1616			if (unlikely(seqno == acked + 1 &&
1617				     link_retransmit_failure(l, r, rc))) {
1618				/* Ignore this bc Gap ACKs if any */
1619				kfree(this_ga);
1620				this_ga = NULL;
1621				break;
1622			}
1623			/* retransmit skb if unrestricted*/
1624			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1625				continue;
1626			tipc_link_set_skb_retransmit_time(skb, l);
1627			_skb = pskb_copy(skb, GFP_ATOMIC);
1628			if (!_skb)
1629				continue;
1630			hdr = buf_msg(_skb);
1631			msg_set_ack(hdr, ack);
1632			msg_set_bcast_ack(hdr, bc_ack);
1633			_skb->priority = TC_PRIO_CONTROL;
1634			__skb_queue_tail(xmitq, _skb);
1635			l->stats.retransmitted++;
1636			if (!is_uc)
1637				r->stats.retransmitted++;
1638			*retransmitted = true;
1639			/* Increase actual retrans counter & mark first time */
1640			if (!TIPC_SKB_CB(skb)->retr_cnt++)
1641				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1642		} else {
1643			/* retry with Gap ACK blocks if any */
1644			if (n >= gack_cnt)
1645				break;
1646			nacked = ntohs(gacks[n].ack);
1647			ngap = ntohs(gacks[n].gap);
1648			n++;
1649			goto next_gap_ack;
1650		}
1651	}
1652
1653	/* Renew last Gap ACK blocks for bc if needed */
1654	if (bc_has_acked) {
1655		if (this_ga) {
1656			kfree(last_ga);
1657			r->last_ga = this_ga;
1658			r->last_gap = gap;
1659		} else if (last_ga) {
1660			if (less(acked, start)) {
1661				si--;
1662				offset = start - acked - 1;
1663			} else if (less(acked, end)) {
1664				acked = end;
1665			}
1666			if (si < last_ga->bgack_cnt) {
1667				last_ga->start_index = si;
1668				r->last_gap = offset;
1669			} else {
1670				kfree(last_ga);
1671				r->last_ga = NULL;
1672				r->last_gap = 0;
1673			}
1674		} else {
1675			r->last_gap = 0;
1676		}
1677		r->acked = acked;
1678	} else {
1679		kfree(this_ga);
1680	}
1681
1682	return qlen - skb_queue_len(&l->transmq);
1683}
1684
1685/* tipc_link_build_state_msg: prepare link state message for transmission
1686 *
1687 * Note that sending of broadcast ack is coordinated among nodes, to reduce
1688 * risk of ack storms towards the sender
1689 */
1690int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1691{
1692	if (!l)
1693		return 0;
1694
1695	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1696	if (link_is_bc_rcvlink(l)) {
1697		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1698			return 0;
1699		l->rcv_unacked = 0;
1700
1701		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1702		l->snd_nxt = l->rcv_nxt;
1703		return TIPC_LINK_SND_STATE;
1704	}
1705	/* Unicast ACK */
1706	l->rcv_unacked = 0;
1707	l->stats.sent_acks++;
1708	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1709	return 0;
1710}
1711
1712/* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1713 */
1714void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1715{
1716	int mtyp = RESET_MSG;
1717	struct sk_buff *skb;
1718
1719	if (l->state == LINK_ESTABLISHING)
1720		mtyp = ACTIVATE_MSG;
1721
1722	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1723
1724	/* Inform peer that this endpoint is going down if applicable */
1725	skb = skb_peek_tail(xmitq);
1726	if (skb && (l->state == LINK_RESET))
1727		msg_set_peer_stopping(buf_msg(skb), 1);
1728}
1729
1730/* tipc_link_build_nack_msg: prepare link nack message for transmission
1731 * Note that sending of broadcast NACK is coordinated among nodes, to
1732 * reduce the risk of NACK storms towards the sender
1733 */
1734static int tipc_link_build_nack_msg(struct tipc_link *l,
1735				    struct sk_buff_head *xmitq)
1736{
1737	u32 def_cnt = ++l->stats.deferred_recv;
1738	struct sk_buff_head *dfq = &l->deferdq;
1739	u32 defq_len = skb_queue_len(dfq);
1740	int match1, match2;
1741
1742	if (link_is_bc_rcvlink(l)) {
1743		match1 = def_cnt & 0xf;
1744		match2 = tipc_own_addr(l->net) & 0xf;
1745		if (match1 == match2)
1746			return TIPC_LINK_SND_STATE;
1747		return 0;
1748	}
1749
1750	if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1751		u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1752
1753		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1754					  rcvgap, 0, 0, xmitq);
1755	}
1756	return 0;
1757}
1758
1759/* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1760 * @l: the link that should handle the message
1761 * @skb: TIPC packet
1762 * @xmitq: queue to place packets to be sent after this call
1763 */
1764int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1765		  struct sk_buff_head *xmitq)
1766{
1767	struct sk_buff_head *defq = &l->deferdq;
1768	struct tipc_msg *hdr = buf_msg(skb);
1769	u16 seqno, rcv_nxt, win_lim;
1770	int released = 0;
1771	int rc = 0;
1772
1773	/* Verify and update link state */
1774	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1775		return tipc_link_proto_rcv(l, skb, xmitq);
1776
1777	/* Don't send probe at next timeout expiration */
1778	l->silent_intv_cnt = 0;
1779
1780	do {
1781		hdr = buf_msg(skb);
1782		seqno = msg_seqno(hdr);
1783		rcv_nxt = l->rcv_nxt;
1784		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1785
1786		if (unlikely(!tipc_link_is_up(l))) {
1787			if (l->state == LINK_ESTABLISHING)
1788				rc = TIPC_LINK_UP_EVT;
1789			kfree_skb(skb);
1790			break;
1791		}
1792
1793		/* Drop if outside receive window */
1794		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1795			l->stats.duplicates++;
1796			kfree_skb(skb);
1797			break;
1798		}
1799		released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1800						      NULL, NULL, NULL, NULL);
1801
1802		/* Defer delivery if sequence gap */
1803		if (unlikely(seqno != rcv_nxt)) {
1804			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1805				l->stats.duplicates++;
1806			rc |= tipc_link_build_nack_msg(l, xmitq);
1807			break;
1808		}
1809
1810		/* Deliver packet */
1811		l->rcv_nxt++;
1812		l->stats.recv_pkts++;
1813
1814		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1815			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1816		else if (!tipc_data_input(l, skb, l->inputq))
1817			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1818		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1819			rc |= tipc_link_build_state_msg(l, xmitq);
1820		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1821			break;
1822	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1823
1824	/* Forward queues and wake up waiting users */
1825	if (released) {
1826		tipc_link_update_cwin(l, released, 0);
1827		tipc_link_advance_backlog(l, xmitq);
1828		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1829			link_prepare_wakeup(l);
1830	}
1831	return rc;
1832}
1833
1834static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1835				      bool probe_reply, u16 rcvgap,
1836				      int tolerance, int priority,
1837				      struct sk_buff_head *xmitq)
1838{
1839	struct tipc_mon_state *mstate = &l->mon_state;
1840	struct sk_buff_head *dfq = &l->deferdq;
1841	struct tipc_link *bcl = l->bc_rcvlink;
1842	struct tipc_msg *hdr;
1843	struct sk_buff *skb;
1844	bool node_up = tipc_link_is_up(bcl);
1845	u16 glen = 0, bc_rcvgap = 0;
1846	int dlen = 0;
1847	void *data;
1848
1849	/* Don't send protocol message during reset or link failover */
1850	if (tipc_link_is_blocked(l))
1851		return;
1852
1853	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1854		return;
1855
1856	if ((probe || probe_reply) && !skb_queue_empty(dfq))
1857		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1858
1859	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1860			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1861			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
1862	if (!skb)
1863		return;
1864
1865	hdr = buf_msg(skb);
1866	data = msg_data(hdr);
1867	msg_set_session(hdr, l->session);
1868	msg_set_bearer_id(hdr, l->bearer_id);
1869	msg_set_net_plane(hdr, l->net_plane);
1870	msg_set_next_sent(hdr, l->snd_nxt);
1871	msg_set_ack(hdr, l->rcv_nxt - 1);
1872	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1873	msg_set_bc_ack_invalid(hdr, !node_up);
1874	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1875	msg_set_link_tolerance(hdr, tolerance);
1876	msg_set_linkprio(hdr, priority);
1877	msg_set_redundant_link(hdr, node_up);
1878	msg_set_seq_gap(hdr, 0);
1879	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1880
1881	if (mtyp == STATE_MSG) {
1882		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1883			msg_set_seqno(hdr, l->snd_nxt_state++);
1884		msg_set_seq_gap(hdr, rcvgap);
1885		bc_rcvgap = link_bc_rcv_gap(bcl);
1886		msg_set_bc_gap(hdr, bc_rcvgap);
1887		msg_set_probe(hdr, probe);
1888		msg_set_is_keepalive(hdr, probe || probe_reply);
1889		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1890			glen = tipc_build_gap_ack_blks(l, hdr);
1891		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1892		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1893		skb_trim(skb, INT_H_SIZE + glen + dlen);
1894		l->stats.sent_states++;
1895		l->rcv_unacked = 0;
1896	} else {
1897		/* RESET_MSG or ACTIVATE_MSG */
1898		if (mtyp == ACTIVATE_MSG) {
1899			msg_set_dest_session_valid(hdr, 1);
1900			msg_set_dest_session(hdr, l->peer_session);
1901		}
1902		msg_set_max_pkt(hdr, l->advertised_mtu);
1903		strcpy(data, l->if_name);
1904		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1905		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1906	}
1907	if (probe)
1908		l->stats.sent_probes++;
1909	if (rcvgap)
1910		l->stats.sent_nacks++;
1911	if (bc_rcvgap)
1912		bcl->stats.sent_nacks++;
1913	skb->priority = TC_PRIO_CONTROL;
1914	__skb_queue_tail(xmitq, skb);
1915	trace_tipc_proto_build(skb, false, l->name);
1916}
1917
1918void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1919				    struct sk_buff_head *xmitq)
1920{
1921	u32 onode = tipc_own_addr(l->net);
1922	struct tipc_msg *hdr, *ihdr;
1923	struct sk_buff_head tnlq;
1924	struct sk_buff *skb;
1925	u32 dnode = l->addr;
1926
1927	__skb_queue_head_init(&tnlq);
1928	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1929			      INT_H_SIZE, BASIC_H_SIZE,
1930			      dnode, onode, 0, 0, 0);
1931	if (!skb) {
1932		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1933		return;
1934	}
1935
1936	hdr = buf_msg(skb);
1937	msg_set_msgcnt(hdr, 1);
1938	msg_set_bearer_id(hdr, l->peer_bearer_id);
1939
1940	ihdr = (struct tipc_msg *)msg_data(hdr);
1941	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1942		      BASIC_H_SIZE, dnode);
1943	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1944	__skb_queue_tail(&tnlq, skb);
1945	tipc_link_xmit(l, &tnlq, xmitq);
1946}
1947
1948/* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1949 * with contents of the link's transmit and backlog queues.
1950 */
1951void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1952			   int mtyp, struct sk_buff_head *xmitq)
1953{
1954	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1955	struct sk_buff *skb, *tnlskb;
1956	struct tipc_msg *hdr, tnlhdr;
1957	struct sk_buff_head *queue = &l->transmq;
1958	struct sk_buff_head tmpxq, tnlq, frags;
1959	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1960	bool pktcnt_need_update = false;
1961	u16 syncpt;
1962	int rc;
1963
1964	if (!tnl)
1965		return;
1966
1967	__skb_queue_head_init(&tnlq);
1968	/* Link Synching:
1969	 * From now on, send only one single ("dummy") SYNCH message
1970	 * to peer. The SYNCH message does not contain any data, just
1971	 * a header conveying the synch point to the peer.
1972	 */
1973	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1974		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1975					 INT_H_SIZE, 0, l->addr,
1976					 tipc_own_addr(l->net),
1977					 0, 0, 0);
1978		if (!tnlskb) {
1979			pr_warn("%sunable to create dummy SYNCH_MSG\n",
1980				link_co_err);
1981			return;
1982		}
1983
1984		hdr = buf_msg(tnlskb);
1985		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
1986		msg_set_syncpt(hdr, syncpt);
1987		msg_set_bearer_id(hdr, l->peer_bearer_id);
1988		__skb_queue_tail(&tnlq, tnlskb);
1989		tipc_link_xmit(tnl, &tnlq, xmitq);
1990		return;
1991	}
1992
1993	__skb_queue_head_init(&tmpxq);
1994	__skb_queue_head_init(&frags);
1995	/* At least one packet required for safe algorithm => add dummy */
1996	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1997			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
1998			      0, 0, TIPC_ERR_NO_PORT);
1999	if (!skb) {
2000		pr_warn("%sunable to create tunnel packet\n", link_co_err);
2001		return;
2002	}
2003	__skb_queue_tail(&tnlq, skb);
2004	tipc_link_xmit(l, &tnlq, &tmpxq);
2005	__skb_queue_purge(&tmpxq);
2006
2007	/* Initialize reusable tunnel packet header */
2008	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
2009		      mtyp, INT_H_SIZE, l->addr);
2010	if (mtyp == SYNCH_MSG)
2011		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
2012	else
2013		pktcnt = skb_queue_len(&l->transmq);
2014	pktcnt += skb_queue_len(&l->backlogq);
2015	msg_set_msgcnt(&tnlhdr, pktcnt);
2016	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
2017tnl:
2018	/* Wrap each packet into a tunnel packet */
2019	skb_queue_walk(queue, skb) {
2020		hdr = buf_msg(skb);
2021		if (queue == &l->backlogq)
2022			msg_set_seqno(hdr, seqno++);
2023		pktlen = msg_size(hdr);
2024
2025		/* Tunnel link MTU is not large enough? This could be
2026		 * due to:
2027		 * 1) Link MTU has just changed or set differently;
2028		 * 2) Or FAILOVER on the top of a SYNCH message
2029		 *
2030		 * The 2nd case should not happen if peer supports
2031		 * TIPC_TUNNEL_ENHANCED
2032		 */
2033		if (pktlen > tnl->mtu - INT_H_SIZE) {
2034			if (mtyp == FAILOVER_MSG &&
2035			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
2036				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
2037						       &frags);
2038				if (rc) {
2039					pr_warn("%sunable to frag msg: rc %d\n",
2040						link_co_err, rc);
2041					return;
2042				}
2043				pktcnt += skb_queue_len(&frags) - 1;
2044				pktcnt_need_update = true;
2045				skb_queue_splice_tail_init(&frags, &tnlq);
2046				continue;
2047			}
2048			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2049			 * => Just warn it and return!
2050			 */
2051			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2052					    link_co_err, msg_user(hdr),
2053					    msg_type(hdr), msg_size(hdr));
2054			return;
2055		}
2056
2057		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2058		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2059		if (!tnlskb) {
2060			pr_warn("%sunable to send packet\n", link_co_err);
2061			return;
2062		}
2063		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2064		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2065		__skb_queue_tail(&tnlq, tnlskb);
2066	}
2067	if (queue != &l->backlogq) {
2068		queue = &l->backlogq;
2069		goto tnl;
2070	}
2071
2072	if (pktcnt_need_update)
2073		skb_queue_walk(&tnlq, skb) {
2074			hdr = buf_msg(skb);
2075			msg_set_msgcnt(hdr, pktcnt);
2076		}
2077
2078	tipc_link_xmit(tnl, &tnlq, xmitq);
2079
2080	if (mtyp == FAILOVER_MSG) {
2081		tnl->drop_point = l->rcv_nxt;
2082		tnl->failover_reasm_skb = l->reasm_buf;
2083		l->reasm_buf = NULL;
2084
2085		/* Failover the link's deferdq */
2086		if (unlikely(!skb_queue_empty(fdefq))) {
2087			pr_warn("Link failover deferdq not empty: %d!\n",
2088				skb_queue_len(fdefq));
2089			__skb_queue_purge(fdefq);
2090		}
2091		skb_queue_splice_init(&l->deferdq, fdefq);
2092	}
2093}
2094
2095/**
2096 * tipc_link_failover_prepare() - prepare tnl for link failover
2097 *
2098 * This is a special version of the precursor - tipc_link_tnl_prepare(),
2099 * see the tipc_node_link_failover() for details
2100 *
2101 * @l: failover link
2102 * @tnl: tunnel link
2103 * @xmitq: queue for messages to be xmited
2104 */
2105void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2106				struct sk_buff_head *xmitq)
2107{
2108	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2109
2110	tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2111
2112	/* This failover link endpoint was never established before,
2113	 * so it has not received anything from peer.
2114	 * Otherwise, it must be a normal failover situation or the
2115	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2116	 * would have to start over from scratch instead.
2117	 */
2118	tnl->drop_point = 1;
2119	tnl->failover_reasm_skb = NULL;
2120
2121	/* Initiate the link's failover deferdq */
2122	if (unlikely(!skb_queue_empty(fdefq))) {
2123		pr_warn("Link failover deferdq not empty: %d!\n",
2124			skb_queue_len(fdefq));
2125		__skb_queue_purge(fdefq);
2126	}
2127}
2128
2129/* tipc_link_validate_msg(): validate message against current link state
2130 * Returns true if message should be accepted, otherwise false
2131 */
2132bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2133{
2134	u16 curr_session = l->peer_session;
2135	u16 session = msg_session(hdr);
2136	int mtyp = msg_type(hdr);
2137
2138	if (msg_user(hdr) != LINK_PROTOCOL)
2139		return true;
2140
2141	switch (mtyp) {
2142	case RESET_MSG:
2143		if (!l->in_session)
2144			return true;
2145		/* Accept only RESET with new session number */
2146		return more(session, curr_session);
2147	case ACTIVATE_MSG:
2148		if (!l->in_session)
2149			return true;
2150		/* Accept only ACTIVATE with new or current session number */
2151		return !less(session, curr_session);
2152	case STATE_MSG:
2153		/* Accept only STATE with current session number */
2154		if (!l->in_session)
2155			return false;
2156		if (session != curr_session)
2157			return false;
2158		/* Extra sanity check */
2159		if (!tipc_link_is_up(l) && msg_ack(hdr))
2160			return false;
2161		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2162			return true;
2163		/* Accept only STATE with new sequence number */
2164		return !less(msg_seqno(hdr), l->rcv_nxt_state);
2165	default:
2166		return false;
2167	}
2168}
2169
2170/* tipc_link_proto_rcv(): receive link level protocol message :
2171 * Note that network plane id propagates through the network, and may
2172 * change at any time. The node with lowest numerical id determines
2173 * network plane
2174 */
2175static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2176			       struct sk_buff_head *xmitq)
2177{
2178	struct tipc_msg *hdr = buf_msg(skb);
2179	struct tipc_gap_ack_blks *ga = NULL;
2180	bool reply = msg_probe(hdr), retransmitted = false;
2181	u32 dlen = msg_data_sz(hdr), glen = 0, msg_max;
2182	u16 peers_snd_nxt =  msg_next_sent(hdr);
2183	u16 peers_tol = msg_link_tolerance(hdr);
2184	u16 peers_prio = msg_linkprio(hdr);
2185	u16 gap = msg_seq_gap(hdr);
2186	u16 ack = msg_ack(hdr);
2187	u16 rcv_nxt = l->rcv_nxt;
2188	u16 rcvgap = 0;
2189	int mtyp = msg_type(hdr);
2190	int rc = 0, released;
2191	char *if_name;
2192	void *data;
2193
2194	trace_tipc_proto_rcv(skb, false, l->name);
2195
2196	if (dlen > U16_MAX)
2197		goto exit;
2198
2199	if (tipc_link_is_blocked(l) || !xmitq)
2200		goto exit;
2201
2202	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2203		l->net_plane = msg_net_plane(hdr);
2204
2205	if (skb_linearize(skb))
2206		goto exit;
2207
2208	hdr = buf_msg(skb);
2209	data = msg_data(hdr);
2210
2211	if (!tipc_link_validate_msg(l, hdr)) {
2212		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2213		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2214		goto exit;
2215	}
2216
2217	switch (mtyp) {
2218	case RESET_MSG:
2219	case ACTIVATE_MSG:
2220		msg_max = msg_max_pkt(hdr);
2221		if (msg_max < tipc_bearer_min_mtu(l->net, l->bearer_id))
2222			break;
2223		/* Complete own link name with peer's interface name */
2224		if_name =  strrchr(l->name, ':') + 1;
2225		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2226			break;
2227		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2228			break;
2229		strncpy(if_name, data, TIPC_MAX_IF_NAME);
2230
2231		/* Update own tolerance if peer indicates a non-zero value */
2232		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2233			l->tolerance = peers_tol;
2234			l->bc_rcvlink->tolerance = peers_tol;
2235		}
2236		/* Update own priority if peer's priority is higher */
2237		if (tipc_in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2238			l->priority = peers_prio;
2239
2240		/* If peer is going down we want full re-establish cycle */
2241		if (msg_peer_stopping(hdr)) {
2242			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2243			break;
2244		}
2245
2246		/* If this endpoint was re-created while peer was ESTABLISHING
2247		 * it doesn't know current session number. Force re-synch.
2248		 */
2249		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2250		    l->session != msg_dest_session(hdr)) {
2251			if (less(l->session, msg_dest_session(hdr)))
2252				l->session = msg_dest_session(hdr) + 1;
2253			break;
2254		}
2255
2256		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2257		if (mtyp == RESET_MSG || !tipc_link_is_up(l))
2258			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2259
2260		/* ACTIVATE_MSG takes up link if it was already locally reset */
2261		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2262			rc = TIPC_LINK_UP_EVT;
2263
2264		l->peer_session = msg_session(hdr);
2265		l->in_session = true;
2266		l->peer_bearer_id = msg_bearer_id(hdr);
2267		if (l->mtu > msg_max)
2268			l->mtu = msg_max;
2269		break;
2270
2271	case STATE_MSG:
2272		/* Validate Gap ACK blocks, drop if invalid */
2273		glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2274		if (glen > dlen)
2275			break;
2276
2277		l->rcv_nxt_state = msg_seqno(hdr) + 1;
2278
2279		/* Update own tolerance if peer indicates a non-zero value */
2280		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2281			l->tolerance = peers_tol;
2282			l->bc_rcvlink->tolerance = peers_tol;
2283		}
2284		/* Update own prio if peer indicates a different value */
2285		if ((peers_prio != l->priority) &&
2286		    tipc_in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2287			l->priority = peers_prio;
2288			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2289		}
2290
2291		l->silent_intv_cnt = 0;
2292		l->stats.recv_states++;
2293		if (msg_probe(hdr))
2294			l->stats.recv_probes++;
2295
2296		if (!tipc_link_is_up(l)) {
2297			if (l->state == LINK_ESTABLISHING)
2298				rc = TIPC_LINK_UP_EVT;
2299			break;
2300		}
2301
2302		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2303			     &l->mon_state, l->bearer_id);
2304
2305		/* Send NACK if peer has sent pkts we haven't received yet */
2306		if ((reply || msg_is_keepalive(hdr)) &&
2307		    more(peers_snd_nxt, rcv_nxt) &&
2308		    !tipc_link_is_synching(l) &&
2309		    skb_queue_empty(&l->deferdq))
2310			rcvgap = peers_snd_nxt - l->rcv_nxt;
2311		if (rcvgap || reply)
2312			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2313						  rcvgap, 0, 0, xmitq);
2314
2315		released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2316						     &retransmitted, &rc);
2317		if (gap)
2318			l->stats.recv_nacks++;
2319		if (released || retransmitted)
2320			tipc_link_update_cwin(l, released, retransmitted);
2321		if (released)
2322			tipc_link_advance_backlog(l, xmitq);
2323		if (unlikely(!skb_queue_empty(&l->wakeupq)))
2324			link_prepare_wakeup(l);
2325	}
2326exit:
2327	kfree_skb(skb);
2328	return rc;
2329}
2330
2331/* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2332 */
2333static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2334					 u16 peers_snd_nxt,
2335					 struct sk_buff_head *xmitq)
2336{
2337	struct sk_buff *skb;
2338	struct tipc_msg *hdr;
2339	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2340	u16 ack = l->rcv_nxt - 1;
2341	u16 gap_to = peers_snd_nxt - 1;
2342
2343	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2344			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2345	if (!skb)
2346		return false;
2347	hdr = buf_msg(skb);
2348	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2349	msg_set_bcast_ack(hdr, ack);
2350	msg_set_bcgap_after(hdr, ack);
2351	if (dfrd_skb)
2352		gap_to = buf_seqno(dfrd_skb) - 1;
2353	msg_set_bcgap_to(hdr, gap_to);
2354	msg_set_non_seq(hdr, bcast);
2355	__skb_queue_tail(xmitq, skb);
2356	return true;
2357}
2358
2359/* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2360 *
2361 * Give a newly added peer node the sequence number where it should
2362 * start receiving and acking broadcast packets.
2363 */
2364static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2365					struct sk_buff_head *xmitq)
2366{
2367	struct sk_buff_head list;
2368
2369	__skb_queue_head_init(&list);
2370	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2371		return;
2372	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2373	tipc_link_xmit(l, &list, xmitq);
2374}
2375
2376/* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2377 */
2378void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2379{
2380	int mtyp = msg_type(hdr);
2381	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2382
2383	if (tipc_link_is_up(l))
2384		return;
2385
2386	if (msg_user(hdr) == BCAST_PROTOCOL) {
2387		l->rcv_nxt = peers_snd_nxt;
2388		l->state = LINK_ESTABLISHED;
2389		return;
2390	}
2391
2392	if (l->peer_caps & TIPC_BCAST_SYNCH)
2393		return;
2394
2395	if (msg_peer_node_is_up(hdr))
2396		return;
2397
2398	/* Compatibility: accept older, less safe initial synch data */
2399	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2400		l->rcv_nxt = peers_snd_nxt;
2401}
2402
2403/* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2404 */
2405int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2406			  struct sk_buff_head *xmitq)
2407{
2408	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2409	int rc = 0;
2410
2411	if (!tipc_link_is_up(l))
2412		return rc;
2413
2414	if (!msg_peer_node_is_up(hdr))
2415		return rc;
2416
2417	/* Open when peer acknowledges our bcast init msg (pkt #1) */
2418	if (msg_ack(hdr))
2419		l->bc_peer_is_up = true;
2420
2421	if (!l->bc_peer_is_up)
2422		return rc;
2423
2424	/* Ignore if peers_snd_nxt goes beyond receive window */
2425	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2426		return rc;
2427
2428	l->snd_nxt = peers_snd_nxt;
2429	if (link_bc_rcv_gap(l))
2430		rc |= TIPC_LINK_SND_STATE;
2431
2432	/* Return now if sender supports nack via STATE messages */
2433	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2434		return rc;
2435
2436	/* Otherwise, be backwards compatible */
2437
2438	if (!more(peers_snd_nxt, l->rcv_nxt)) {
2439		l->nack_state = BC_NACK_SND_CONDITIONAL;
2440		return 0;
2441	}
2442
2443	/* Don't NACK if one was recently sent or peeked */
2444	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2445		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2446		return 0;
2447	}
2448
2449	/* Conditionally delay NACK sending until next synch rcv */
2450	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2451		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2452		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2453			return 0;
2454	}
2455
2456	/* Send NACK now but suppress next one */
2457	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2458	l->nack_state = BC_NACK_SND_SUPPRESS;
2459	return 0;
2460}
2461
2462int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2463			 struct tipc_gap_ack_blks *ga,
2464			 struct sk_buff_head *xmitq,
2465			 struct sk_buff_head *retrq)
2466{
2467	struct tipc_link *l = r->bc_sndlink;
2468	bool unused = false;
2469	int rc = 0;
2470
2471	if (!tipc_link_is_up(r) || !r->bc_peer_is_up)
2472		return 0;
2473
2474	if (gap) {
2475		l->stats.recv_nacks++;
2476		r->stats.recv_nacks++;
2477	}
2478
2479	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2480		return 0;
2481
2482	trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2483	tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2484
2485	tipc_link_advance_backlog(l, xmitq);
2486	if (unlikely(!skb_queue_empty(&l->wakeupq)))
2487		link_prepare_wakeup(l);
2488
2489	return rc;
2490}
2491
2492/* tipc_link_bc_nack_rcv(): receive broadcast nack message
2493 * This function is here for backwards compatibility, since
2494 * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2495 */
2496int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2497			  struct sk_buff_head *xmitq)
2498{
2499	struct tipc_msg *hdr = buf_msg(skb);
2500	u32 dnode = msg_destnode(hdr);
2501	int mtyp = msg_type(hdr);
2502	u16 acked = msg_bcast_ack(hdr);
2503	u16 from = acked + 1;
2504	u16 to = msg_bcgap_to(hdr);
2505	u16 peers_snd_nxt = to + 1;
2506	int rc = 0;
2507
2508	kfree_skb(skb);
2509
2510	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2511		return 0;
2512
2513	if (mtyp != STATE_MSG)
2514		return 0;
2515
2516	if (dnode == tipc_own_addr(l->net)) {
2517		rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2518					  xmitq);
2519		l->stats.recv_nacks++;
2520		return rc;
2521	}
2522
2523	/* Msg for other node => suppress own NACK at next sync if applicable */
2524	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2525		l->nack_state = BC_NACK_SND_SUPPRESS;
2526
2527	return 0;
2528}
2529
2530void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2531{
2532	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2533
2534	l->min_win = min_win;
2535	l->ssthresh = max_win;
2536	l->max_win = max_win;
2537	l->window = min_win;
2538	l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2539	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2540	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2541	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2542	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2543}
2544
2545/**
2546 * tipc_link_reset_stats - reset link statistics
2547 * @l: pointer to link
2548 */
2549void tipc_link_reset_stats(struct tipc_link *l)
2550{
2551	memset(&l->stats, 0, sizeof(l->stats));
2552}
2553
2554static void link_print(struct tipc_link *l, const char *str)
2555{
2556	struct sk_buff *hskb = skb_peek(&l->transmq);
2557	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2558	u16 tail = l->snd_nxt - 1;
2559
2560	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2561	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2562		skb_queue_len(&l->transmq), head, tail,
2563		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2564}
2565
2566/* Parse and validate nested (link) properties valid for media, bearer and link
2567 */
2568int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2569{
2570	int err;
2571
2572	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2573					  tipc_nl_prop_policy, NULL);
2574	if (err)
2575		return err;
2576
2577	if (props[TIPC_NLA_PROP_PRIO]) {
2578		u32 prio;
2579
2580		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2581		if (prio > TIPC_MAX_LINK_PRI)
2582			return -EINVAL;
2583	}
2584
2585	if (props[TIPC_NLA_PROP_TOL]) {
2586		u32 tol;
2587
2588		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2589		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2590			return -EINVAL;
2591	}
2592
2593	if (props[TIPC_NLA_PROP_WIN]) {
2594		u32 max_win;
2595
2596		max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2597		if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2598			return -EINVAL;
2599	}
2600
2601	return 0;
2602}
2603
2604static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2605{
2606	int i;
2607	struct nlattr *stats;
2608
2609	struct nla_map {
2610		u32 key;
2611		u32 val;
2612	};
2613
2614	struct nla_map map[] = {
2615		{TIPC_NLA_STATS_RX_INFO, 0},
2616		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2617		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2618		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2619		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2620		{TIPC_NLA_STATS_TX_INFO, 0},
2621		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2622		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2623		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2624		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2625		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2626			s->msg_length_counts : 1},
2627		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2628		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2629		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2630		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2631		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2632		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2633		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2634		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2635		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2636		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2637		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2638		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2639		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2640		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2641		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2642		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2643		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2644		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2645		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2646		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2647		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2648		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2649			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2650	};
2651
2652	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2653	if (!stats)
2654		return -EMSGSIZE;
2655
2656	for (i = 0; i <  ARRAY_SIZE(map); i++)
2657		if (nla_put_u32(skb, map[i].key, map[i].val))
2658			goto msg_full;
2659
2660	nla_nest_end(skb, stats);
2661
2662	return 0;
2663msg_full:
2664	nla_nest_cancel(skb, stats);
2665
2666	return -EMSGSIZE;
2667}
2668
2669/* Caller should hold appropriate locks to protect the link */
2670int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2671		       struct tipc_link *link, int nlflags)
2672{
2673	u32 self = tipc_own_addr(net);
2674	struct nlattr *attrs;
2675	struct nlattr *prop;
2676	void *hdr;
2677	int err;
2678
2679	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2680			  nlflags, TIPC_NL_LINK_GET);
2681	if (!hdr)
2682		return -EMSGSIZE;
2683
2684	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2685	if (!attrs)
2686		goto msg_full;
2687
2688	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2689		goto attr_msg_full;
2690	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2691		goto attr_msg_full;
2692	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2693		goto attr_msg_full;
2694	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2695		goto attr_msg_full;
2696	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2697		goto attr_msg_full;
2698
2699	if (tipc_link_is_up(link))
2700		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2701			goto attr_msg_full;
2702	if (link->active)
2703		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2704			goto attr_msg_full;
2705
2706	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2707	if (!prop)
2708		goto attr_msg_full;
2709	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2710		goto prop_msg_full;
2711	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2712		goto prop_msg_full;
2713	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2714			link->window))
2715		goto prop_msg_full;
2716	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2717		goto prop_msg_full;
2718	nla_nest_end(msg->skb, prop);
2719
2720	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2721	if (err)
2722		goto attr_msg_full;
2723
2724	nla_nest_end(msg->skb, attrs);
2725	genlmsg_end(msg->skb, hdr);
2726
2727	return 0;
2728
2729prop_msg_full:
2730	nla_nest_cancel(msg->skb, prop);
2731attr_msg_full:
2732	nla_nest_cancel(msg->skb, attrs);
2733msg_full:
2734	genlmsg_cancel(msg->skb, hdr);
2735
2736	return -EMSGSIZE;
2737}
2738
2739static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2740				      struct tipc_stats *stats)
2741{
2742	int i;
2743	struct nlattr *nest;
2744
2745	struct nla_map {
2746		__u32 key;
2747		__u32 val;
2748	};
2749
2750	struct nla_map map[] = {
2751		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2752		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2753		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2754		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2755		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2756		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2757		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2758		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2759		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2760		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2761		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2762		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2763		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2764		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2765		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2766		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2767		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2768		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2769		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2770			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2771	};
2772
2773	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2774	if (!nest)
2775		return -EMSGSIZE;
2776
2777	for (i = 0; i <  ARRAY_SIZE(map); i++)
2778		if (nla_put_u32(skb, map[i].key, map[i].val))
2779			goto msg_full;
2780
2781	nla_nest_end(skb, nest);
2782
2783	return 0;
2784msg_full:
2785	nla_nest_cancel(skb, nest);
2786
2787	return -EMSGSIZE;
2788}
2789
2790int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2791			struct tipc_link *bcl)
2792{
2793	int err;
2794	void *hdr;
2795	struct nlattr *attrs;
2796	struct nlattr *prop;
2797	u32 bc_mode = tipc_bcast_get_mode(net);
2798	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2799
2800	if (!bcl)
2801		return 0;
2802
2803	tipc_bcast_lock(net);
2804
2805	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2806			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2807	if (!hdr) {
2808		tipc_bcast_unlock(net);
2809		return -EMSGSIZE;
2810	}
2811
2812	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2813	if (!attrs)
2814		goto msg_full;
2815
2816	/* The broadcast link is always up */
2817	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2818		goto attr_msg_full;
2819
2820	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2821		goto attr_msg_full;
2822	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2823		goto attr_msg_full;
2824	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2825		goto attr_msg_full;
2826	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2827		goto attr_msg_full;
2828
2829	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2830	if (!prop)
2831		goto attr_msg_full;
2832	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2833		goto prop_msg_full;
2834	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2835		goto prop_msg_full;
2836	if (bc_mode & BCLINK_MODE_SEL)
2837		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2838				bc_ratio))
2839			goto prop_msg_full;
2840	nla_nest_end(msg->skb, prop);
2841
2842	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2843	if (err)
2844		goto attr_msg_full;
2845
2846	tipc_bcast_unlock(net);
2847	nla_nest_end(msg->skb, attrs);
2848	genlmsg_end(msg->skb, hdr);
2849
2850	return 0;
2851
2852prop_msg_full:
2853	nla_nest_cancel(msg->skb, prop);
2854attr_msg_full:
2855	nla_nest_cancel(msg->skb, attrs);
2856msg_full:
2857	tipc_bcast_unlock(net);
2858	genlmsg_cancel(msg->skb, hdr);
2859
2860	return -EMSGSIZE;
2861}
2862
2863void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2864			     struct sk_buff_head *xmitq)
2865{
2866	l->tolerance = tol;
2867	if (l->bc_rcvlink)
2868		l->bc_rcvlink->tolerance = tol;
2869	if (tipc_link_is_up(l))
2870		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2871}
2872
2873void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2874			struct sk_buff_head *xmitq)
2875{
2876	l->priority = prio;
2877	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2878}
2879
2880void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2881{
2882	l->abort_limit = limit;
2883}
2884
2885/**
2886 * tipc_link_dump - dump TIPC link data
2887 * @l: tipc link to be dumped
2888 * @dqueues: bitmask to decide if any link queue to be dumped?
2889 *           - TIPC_DUMP_NONE: don't dump link queues
2890 *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2891 *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2892 *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2893 *           - TIPC_DUMP_INPUTQ: dump link input queue
2894 *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2895 *           - TIPC_DUMP_ALL: dump all the link queues above
2896 * @buf: returned buffer of dump data in format
2897 */
2898int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2899{
2900	int i = 0;
2901	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2902	struct sk_buff_head *list;
2903	struct sk_buff *hskb, *tskb;
2904	u32 len;
2905
2906	if (!l) {
2907		i += scnprintf(buf, sz, "link data: (null)\n");
2908		return i;
2909	}
2910
2911	i += scnprintf(buf, sz, "link data: %x", l->addr);
2912	i += scnprintf(buf + i, sz - i, " %x", l->state);
2913	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2914	i += scnprintf(buf + i, sz - i, " %u", l->session);
2915	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2916	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2917	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2918	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2919	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2920	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2921	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2922	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2923	i += scnprintf(buf + i, sz - i, " %u", 0);
2924	i += scnprintf(buf + i, sz - i, " %u", 0);
2925	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2926
2927	list = &l->transmq;
2928	len = skb_queue_len(list);
2929	hskb = skb_peek(list);
2930	tskb = skb_peek_tail(list);
2931	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2932		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2933		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2934
2935	list = &l->deferdq;
2936	len = skb_queue_len(list);
2937	hskb = skb_peek(list);
2938	tskb = skb_peek_tail(list);
2939	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2940		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2941		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2942
2943	list = &l->backlogq;
2944	len = skb_queue_len(list);
2945	hskb = skb_peek(list);
2946	tskb = skb_peek_tail(list);
2947	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2948		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2949		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2950
2951	list = l->inputq;
2952	len = skb_queue_len(list);
2953	hskb = skb_peek(list);
2954	tskb = skb_peek_tail(list);
2955	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2956		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2957		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2958
2959	if (dqueues & TIPC_DUMP_TRANSMQ) {
2960		i += scnprintf(buf + i, sz - i, "transmq: ");
2961		i += tipc_list_dump(&l->transmq, false, buf + i);
2962	}
2963	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2964		i += scnprintf(buf + i, sz - i,
2965			       "backlogq: <%u %u %u %u %u>, ",
2966			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2967			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2968			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2969			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2970			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2971		i += tipc_list_dump(&l->backlogq, false, buf + i);
2972	}
2973	if (dqueues & TIPC_DUMP_DEFERDQ) {
2974		i += scnprintf(buf + i, sz - i, "deferdq: ");
2975		i += tipc_list_dump(&l->deferdq, false, buf + i);
2976	}
2977	if (dqueues & TIPC_DUMP_INPUTQ) {
2978		i += scnprintf(buf + i, sz - i, "inputq: ");
2979		i += tipc_list_dump(l->inputq, false, buf + i);
2980	}
2981	if (dqueues & TIPC_DUMP_WAKEUP) {
2982		i += scnprintf(buf + i, sz - i, "wakeup: ");
2983		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2984	}
2985
2986	return i;
2987}
v6.8
   1/*
   2 * net/tipc/link.c: TIPC link code
   3 *
   4 * Copyright (c) 1996-2007, 2012-2016, Ericsson AB
   5 * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
   6 * All rights reserved.
   7 *
   8 * Redistribution and use in source and binary forms, with or without
   9 * modification, are permitted provided that the following conditions are met:
  10 *
  11 * 1. Redistributions of source code must retain the above copyright
  12 *    notice, this list of conditions and the following disclaimer.
  13 * 2. Redistributions in binary form must reproduce the above copyright
  14 *    notice, this list of conditions and the following disclaimer in the
  15 *    documentation and/or other materials provided with the distribution.
  16 * 3. Neither the names of the copyright holders nor the names of its
  17 *    contributors may be used to endorse or promote products derived from
  18 *    this software without specific prior written permission.
  19 *
  20 * Alternatively, this software may be distributed under the terms of the
  21 * GNU General Public License ("GPL") version 2 as published by the Free
  22 * Software Foundation.
  23 *
  24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34 * POSSIBILITY OF SUCH DAMAGE.
  35 */
  36
  37#include "core.h"
  38#include "subscr.h"
  39#include "link.h"
  40#include "bcast.h"
  41#include "socket.h"
  42#include "name_distr.h"
  43#include "discover.h"
  44#include "netlink.h"
  45#include "monitor.h"
  46#include "trace.h"
  47#include "crypto.h"
  48
  49#include <linux/pkt_sched.h>
  50
  51struct tipc_stats {
  52	u32 sent_pkts;
  53	u32 recv_pkts;
  54	u32 sent_states;
  55	u32 recv_states;
  56	u32 sent_probes;
  57	u32 recv_probes;
  58	u32 sent_nacks;
  59	u32 recv_nacks;
  60	u32 sent_acks;
  61	u32 sent_bundled;
  62	u32 sent_bundles;
  63	u32 recv_bundled;
  64	u32 recv_bundles;
  65	u32 retransmitted;
  66	u32 sent_fragmented;
  67	u32 sent_fragments;
  68	u32 recv_fragmented;
  69	u32 recv_fragments;
  70	u32 link_congs;		/* # port sends blocked by congestion */
  71	u32 deferred_recv;
  72	u32 duplicates;
  73	u32 max_queue_sz;	/* send queue size high water mark */
  74	u32 accu_queue_sz;	/* used for send queue size profiling */
  75	u32 queue_sz_counts;	/* used for send queue size profiling */
  76	u32 msg_length_counts;	/* used for message length profiling */
  77	u32 msg_lengths_total;	/* used for message length profiling */
  78	u32 msg_length_profile[7]; /* used for msg. length profiling */
  79};
  80
  81/**
  82 * struct tipc_link - TIPC link data structure
  83 * @addr: network address of link's peer node
  84 * @name: link name character string
  85 * @net: pointer to namespace struct
  86 * @peer_session: link session # being used by peer end of link
  87 * @peer_bearer_id: bearer id used by link's peer endpoint
  88 * @bearer_id: local bearer id used by link
  89 * @tolerance: minimum link continuity loss needed to reset link [in ms]
  90 * @abort_limit: # of unacknowledged continuity probes needed to reset link
  91 * @state: current state of link FSM
  92 * @peer_caps: bitmap describing capabilities of peer node
  93 * @silent_intv_cnt: # of timer intervals without any reception from peer
  94 * @priority: current link priority
  95 * @net_plane: current link network plane ('A' through 'H')
  96 * @mon_state: cookie with information needed by link monitor
  97 * @mtu: current maximum packet size for this link
  98 * @advertised_mtu: advertised own mtu when link is being established
  99 * @backlogq: queue for messages waiting to be sent
 100 * @ackers: # of peers that needs to ack each packet before it can be released
 101 * @acked: # last packet acked by a certain peer. Used for broadcast.
 102 * @rcv_nxt: next sequence number to expect for inbound messages
 103 * @inputq: buffer queue for messages to be delivered upwards
 104 * @namedq: buffer queue for name table messages to be delivered upwards
 105 * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
 106 * @reasm_buf: head of partially reassembled inbound message fragments
 107 * @stats: collects statistics regarding link activity
 108 * @session: session to be used by link
 109 * @snd_nxt_state: next send seq number
 110 * @rcv_nxt_state: next rcv seq number
 111 * @in_session: have received ACTIVATE_MSG from peer
 112 * @active: link is active
 113 * @if_name: associated interface name
 114 * @rst_cnt: link reset counter
 115 * @drop_point: seq number for failover handling (FIXME)
 116 * @failover_reasm_skb: saved failover msg ptr (FIXME)
 117 * @failover_deferdq: deferred message queue for failover processing (FIXME)
 118 * @transmq: the link's transmit queue
 119 * @backlog: link's backlog by priority (importance)
 120 * @snd_nxt: next sequence number to be used
 121 * @rcv_unacked: # messages read by user, but not yet acked back to peer
 122 * @deferdq: deferred receive queue
 123 * @window: sliding window size for congestion handling
 124 * @min_win: minimal send window to be used by link
 125 * @ssthresh: slow start threshold for congestion handling
 126 * @max_win: maximal send window to be used by link
 127 * @cong_acks: congestion acks for congestion avoidance (FIXME)
 128 * @checkpoint: seq number for congestion window size handling
 129 * @reasm_tnlmsg: fragmentation/reassembly area for tunnel protocol message
 130 * @last_gap: last gap ack blocks for bcast (FIXME)
 131 * @last_ga: ptr to gap ack blocks
 132 * @bc_rcvlink: the peer specific link used for broadcast reception
 133 * @bc_sndlink: the namespace global link used for broadcast sending
 134 * @nack_state: bcast nack state
 135 * @bc_peer_is_up: peer has acked the bcast init msg
 136 */
 137struct tipc_link {
 138	u32 addr;
 139	char name[TIPC_MAX_LINK_NAME];
 140	struct net *net;
 141
 142	/* Management and link supervision data */
 143	u16 peer_session;
 144	u16 session;
 145	u16 snd_nxt_state;
 146	u16 rcv_nxt_state;
 147	u32 peer_bearer_id;
 148	u32 bearer_id;
 149	u32 tolerance;
 150	u32 abort_limit;
 151	u32 state;
 152	u16 peer_caps;
 153	bool in_session;
 154	bool active;
 155	u32 silent_intv_cnt;
 156	char if_name[TIPC_MAX_IF_NAME];
 157	u32 priority;
 158	char net_plane;
 159	struct tipc_mon_state mon_state;
 160	u16 rst_cnt;
 161
 162	/* Failover/synch */
 163	u16 drop_point;
 164	struct sk_buff *failover_reasm_skb;
 165	struct sk_buff_head failover_deferdq;
 166
 167	/* Max packet negotiation */
 168	u16 mtu;
 169	u16 advertised_mtu;
 170
 171	/* Sending */
 172	struct sk_buff_head transmq;
 173	struct sk_buff_head backlogq;
 174	struct {
 175		u16 len;
 176		u16 limit;
 177		struct sk_buff *target_bskb;
 178	} backlog[5];
 179	u16 snd_nxt;
 180
 181	/* Reception */
 182	u16 rcv_nxt;
 183	u32 rcv_unacked;
 184	struct sk_buff_head deferdq;
 185	struct sk_buff_head *inputq;
 186	struct sk_buff_head *namedq;
 187
 188	/* Congestion handling */
 189	struct sk_buff_head wakeupq;
 190	u16 window;
 191	u16 min_win;
 192	u16 ssthresh;
 193	u16 max_win;
 194	u16 cong_acks;
 195	u16 checkpoint;
 196
 197	/* Fragmentation/reassembly */
 198	struct sk_buff *reasm_buf;
 199	struct sk_buff *reasm_tnlmsg;
 200
 201	/* Broadcast */
 202	u16 ackers;
 203	u16 acked;
 204	u16 last_gap;
 205	struct tipc_gap_ack_blks *last_ga;
 206	struct tipc_link *bc_rcvlink;
 207	struct tipc_link *bc_sndlink;
 208	u8 nack_state;
 209	bool bc_peer_is_up;
 210
 211	/* Statistics */
 212	struct tipc_stats stats;
 213};
 214
 215/*
 216 * Error message prefixes
 217 */
 218static const char *link_co_err = "Link tunneling error, ";
 219static const char *link_rst_msg = "Resetting link ";
 220
 221/* Send states for broadcast NACKs
 222 */
 223enum {
 224	BC_NACK_SND_CONDITIONAL,
 225	BC_NACK_SND_UNCONDITIONAL,
 226	BC_NACK_SND_SUPPRESS,
 227};
 228
 229#define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
 230#define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))
 231
 232/* Link FSM states:
 233 */
 234enum {
 235	LINK_ESTABLISHED     = 0xe,
 236	LINK_ESTABLISHING    = 0xe  << 4,
 237	LINK_RESET           = 0x1  << 8,
 238	LINK_RESETTING       = 0x2  << 12,
 239	LINK_PEER_RESET      = 0xd  << 16,
 240	LINK_FAILINGOVER     = 0xf  << 20,
 241	LINK_SYNCHING        = 0xc  << 24
 242};
 243
 244/* Link FSM state checking routines
 245 */
 246static int link_is_up(struct tipc_link *l)
 247{
 248	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
 249}
 250
 251static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 252			       struct sk_buff_head *xmitq);
 253static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 254				      bool probe_reply, u16 rcvgap,
 255				      int tolerance, int priority,
 256				      struct sk_buff_head *xmitq);
 257static void link_print(struct tipc_link *l, const char *str);
 258static int tipc_link_build_nack_msg(struct tipc_link *l,
 259				    struct sk_buff_head *xmitq);
 260static void tipc_link_build_bc_init_msg(struct tipc_link *l,
 261					struct sk_buff_head *xmitq);
 262static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
 263				    struct tipc_link *l, u8 start_index);
 264static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr);
 265static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
 266				     u16 acked, u16 gap,
 267				     struct tipc_gap_ack_blks *ga,
 268				     struct sk_buff_head *xmitq,
 269				     bool *retransmitted, int *rc);
 270static void tipc_link_update_cwin(struct tipc_link *l, int released,
 271				  bool retransmitted);
 272/*
 273 *  Simple non-static link routines (i.e. referenced outside this file)
 274 */
 275bool tipc_link_is_up(struct tipc_link *l)
 276{
 277	return link_is_up(l);
 278}
 279
 280bool tipc_link_peer_is_down(struct tipc_link *l)
 281{
 282	return l->state == LINK_PEER_RESET;
 283}
 284
 285bool tipc_link_is_reset(struct tipc_link *l)
 286{
 287	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 288}
 289
 290bool tipc_link_is_establishing(struct tipc_link *l)
 291{
 292	return l->state == LINK_ESTABLISHING;
 293}
 294
 295bool tipc_link_is_synching(struct tipc_link *l)
 296{
 297	return l->state == LINK_SYNCHING;
 298}
 299
 300bool tipc_link_is_failingover(struct tipc_link *l)
 301{
 302	return l->state == LINK_FAILINGOVER;
 303}
 304
 305bool tipc_link_is_blocked(struct tipc_link *l)
 306{
 307	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
 308}
 309
 310static bool link_is_bc_sndlink(struct tipc_link *l)
 311{
 312	return !l->bc_sndlink;
 313}
 314
 315static bool link_is_bc_rcvlink(struct tipc_link *l)
 316{
 317	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
 318}
 319
 320void tipc_link_set_active(struct tipc_link *l, bool active)
 321{
 322	l->active = active;
 323}
 324
 325u32 tipc_link_id(struct tipc_link *l)
 326{
 327	return l->peer_bearer_id << 16 | l->bearer_id;
 328}
 329
 330int tipc_link_min_win(struct tipc_link *l)
 331{
 332	return l->min_win;
 333}
 334
 335int tipc_link_max_win(struct tipc_link *l)
 336{
 337	return l->max_win;
 338}
 339
 340int tipc_link_prio(struct tipc_link *l)
 341{
 342	return l->priority;
 343}
 344
 345unsigned long tipc_link_tolerance(struct tipc_link *l)
 346{
 347	return l->tolerance;
 348}
 349
 350struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
 351{
 352	return l->inputq;
 353}
 354
 355char tipc_link_plane(struct tipc_link *l)
 356{
 357	return l->net_plane;
 358}
 359
 360struct net *tipc_link_net(struct tipc_link *l)
 361{
 362	return l->net;
 363}
 364
 365void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
 366{
 367	l->peer_caps = capabilities;
 368}
 369
 370void tipc_link_add_bc_peer(struct tipc_link *snd_l,
 371			   struct tipc_link *uc_l,
 372			   struct sk_buff_head *xmitq)
 373{
 374	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
 375
 376	snd_l->ackers++;
 377	rcv_l->acked = snd_l->snd_nxt - 1;
 378	snd_l->state = LINK_ESTABLISHED;
 379	tipc_link_build_bc_init_msg(uc_l, xmitq);
 380}
 381
 382void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
 383			      struct tipc_link *rcv_l,
 384			      struct sk_buff_head *xmitq)
 385{
 386	u16 ack = snd_l->snd_nxt - 1;
 387
 388	snd_l->ackers--;
 389	rcv_l->bc_peer_is_up = true;
 390	rcv_l->state = LINK_ESTABLISHED;
 391	tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
 392	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
 393	tipc_link_reset(rcv_l);
 394	rcv_l->state = LINK_RESET;
 395	if (!snd_l->ackers) {
 396		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
 397		tipc_link_reset(snd_l);
 398		snd_l->state = LINK_RESET;
 399		__skb_queue_purge(xmitq);
 400	}
 401}
 402
 403int tipc_link_bc_peers(struct tipc_link *l)
 404{
 405	return l->ackers;
 406}
 407
 408static u16 link_bc_rcv_gap(struct tipc_link *l)
 409{
 410	struct sk_buff *skb = skb_peek(&l->deferdq);
 411	u16 gap = 0;
 412
 413	if (more(l->snd_nxt, l->rcv_nxt))
 414		gap = l->snd_nxt - l->rcv_nxt;
 415	if (skb)
 416		gap = buf_seqno(skb) - l->rcv_nxt;
 417	return gap;
 418}
 419
 420void tipc_link_set_mtu(struct tipc_link *l, int mtu)
 421{
 422	l->mtu = mtu;
 423}
 424
 425int tipc_link_mtu(struct tipc_link *l)
 426{
 427	return l->mtu;
 428}
 429
 430int tipc_link_mss(struct tipc_link *l)
 431{
 432#ifdef CONFIG_TIPC_CRYPTO
 433	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
 434#else
 435	return l->mtu - INT_H_SIZE;
 436#endif
 437}
 438
 439u16 tipc_link_rcv_nxt(struct tipc_link *l)
 440{
 441	return l->rcv_nxt;
 442}
 443
 444u16 tipc_link_acked(struct tipc_link *l)
 445{
 446	return l->acked;
 447}
 448
 449char *tipc_link_name(struct tipc_link *l)
 450{
 451	return l->name;
 452}
 453
 454u32 tipc_link_state(struct tipc_link *l)
 455{
 456	return l->state;
 457}
 458
 459/**
 460 * tipc_link_create - create a new link
 461 * @net: pointer to associated network namespace
 462 * @if_name: associated interface name
 463 * @bearer_id: id (index) of associated bearer
 464 * @tolerance: link tolerance to be used by link
 465 * @net_plane: network plane (A,B,c..) this link belongs to
 466 * @mtu: mtu to be advertised by link
 467 * @priority: priority to be used by link
 468 * @min_win: minimal send window to be used by link
 469 * @max_win: maximal send window to be used by link
 470 * @session: session to be used by link
 471 * @peer: node id of peer node
 472 * @peer_caps: bitmap describing peer node capabilities
 473 * @bc_sndlink: the namespace global link used for broadcast sending
 474 * @bc_rcvlink: the peer specific link used for broadcast reception
 475 * @inputq: queue to put messages ready for delivery
 476 * @namedq: queue to put binding table update messages ready for delivery
 477 * @link: return value, pointer to put the created link
 478 * @self: local unicast link id
 479 * @peer_id: 128-bit ID of peer
 480 *
 481 * Return: true if link was created, otherwise false
 482 */
 483bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
 484		      int tolerance, char net_plane, u32 mtu, int priority,
 485		      u32 min_win, u32 max_win, u32 session, u32 self,
 486		      u32 peer, u8 *peer_id, u16 peer_caps,
 487		      struct tipc_link *bc_sndlink,
 488		      struct tipc_link *bc_rcvlink,
 489		      struct sk_buff_head *inputq,
 490		      struct sk_buff_head *namedq,
 491		      struct tipc_link **link)
 492{
 493	char peer_str[NODE_ID_STR_LEN] = {0,};
 494	char self_str[NODE_ID_STR_LEN] = {0,};
 495	struct tipc_link *l;
 496
 497	l = kzalloc(sizeof(*l), GFP_ATOMIC);
 498	if (!l)
 499		return false;
 500	*link = l;
 501	l->session = session;
 502
 503	/* Set link name for unicast links only */
 504	if (peer_id) {
 505		tipc_nodeid2string(self_str, tipc_own_id(net));
 506		if (strlen(self_str) > 16)
 507			sprintf(self_str, "%x", self);
 508		tipc_nodeid2string(peer_str, peer_id);
 509		if (strlen(peer_str) > 16)
 510			sprintf(peer_str, "%x", peer);
 511	}
 512	/* Peer i/f name will be completed by reset/activate message */
 513	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
 514		 self_str, if_name, peer_str);
 515
 516	strcpy(l->if_name, if_name);
 517	l->addr = peer;
 518	l->peer_caps = peer_caps;
 519	l->net = net;
 520	l->in_session = false;
 521	l->bearer_id = bearer_id;
 522	l->tolerance = tolerance;
 523	if (bc_rcvlink)
 524		bc_rcvlink->tolerance = tolerance;
 525	l->net_plane = net_plane;
 526	l->advertised_mtu = mtu;
 527	l->mtu = mtu;
 528	l->priority = priority;
 529	tipc_link_set_queue_limits(l, min_win, max_win);
 530	l->ackers = 1;
 531	l->bc_sndlink = bc_sndlink;
 532	l->bc_rcvlink = bc_rcvlink;
 533	l->inputq = inputq;
 534	l->namedq = namedq;
 535	l->state = LINK_RESETTING;
 536	__skb_queue_head_init(&l->transmq);
 537	__skb_queue_head_init(&l->backlogq);
 538	__skb_queue_head_init(&l->deferdq);
 539	__skb_queue_head_init(&l->failover_deferdq);
 540	skb_queue_head_init(&l->wakeupq);
 541	skb_queue_head_init(l->inputq);
 542	return true;
 543}
 544
 545/**
 546 * tipc_link_bc_create - create new link to be used for broadcast
 547 * @net: pointer to associated network namespace
 548 * @mtu: mtu to be used initially if no peers
 549 * @min_win: minimal send window to be used by link
 550 * @max_win: maximal send window to be used by link
 551 * @inputq: queue to put messages ready for delivery
 552 * @namedq: queue to put binding table update messages ready for delivery
 553 * @link: return value, pointer to put the created link
 554 * @ownnode: identity of own node
 555 * @peer: node id of peer node
 556 * @peer_id: 128-bit ID of peer
 557 * @peer_caps: bitmap describing peer node capabilities
 558 * @bc_sndlink: the namespace global link used for broadcast sending
 559 *
 560 * Return: true if link was created, otherwise false
 561 */
 562bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
 563			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
 564			 struct sk_buff_head *inputq,
 565			 struct sk_buff_head *namedq,
 566			 struct tipc_link *bc_sndlink,
 567			 struct tipc_link **link)
 568{
 569	struct tipc_link *l;
 570
 571	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
 572			      max_win, 0, ownnode, peer, NULL, peer_caps,
 573			      bc_sndlink, NULL, inputq, namedq, link))
 574		return false;
 575
 576	l = *link;
 577	if (peer_id) {
 578		char peer_str[NODE_ID_STR_LEN] = {0,};
 579
 580		tipc_nodeid2string(peer_str, peer_id);
 581		if (strlen(peer_str) > 16)
 582			sprintf(peer_str, "%x", peer);
 583		/* Broadcast receiver link name: "broadcast-link:<peer>" */
 584		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
 585			 peer_str);
 586	} else {
 587		strcpy(l->name, tipc_bclink_name);
 588	}
 589	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
 590	tipc_link_reset(l);
 591	l->state = LINK_RESET;
 592	l->ackers = 0;
 593	l->bc_rcvlink = l;
 594
 595	/* Broadcast send link is always up */
 596	if (link_is_bc_sndlink(l))
 597		l->state = LINK_ESTABLISHED;
 598
 599	/* Disable replicast if even a single peer doesn't support it */
 600	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
 601		tipc_bcast_toggle_rcast(net, false);
 602
 603	return true;
 604}
 605
 606/**
 607 * tipc_link_fsm_evt - link finite state machine
 608 * @l: pointer to link
 609 * @evt: state machine event to be processed
 610 */
 611int tipc_link_fsm_evt(struct tipc_link *l, int evt)
 612{
 613	int rc = 0;
 614	int old_state = l->state;
 615
 616	switch (l->state) {
 617	case LINK_RESETTING:
 618		switch (evt) {
 619		case LINK_PEER_RESET_EVT:
 620			l->state = LINK_PEER_RESET;
 621			break;
 622		case LINK_RESET_EVT:
 623			l->state = LINK_RESET;
 624			break;
 625		case LINK_FAILURE_EVT:
 626		case LINK_FAILOVER_BEGIN_EVT:
 627		case LINK_ESTABLISH_EVT:
 628		case LINK_FAILOVER_END_EVT:
 629		case LINK_SYNCH_BEGIN_EVT:
 630		case LINK_SYNCH_END_EVT:
 631		default:
 632			goto illegal_evt;
 633		}
 634		break;
 635	case LINK_RESET:
 636		switch (evt) {
 637		case LINK_PEER_RESET_EVT:
 638			l->state = LINK_ESTABLISHING;
 639			break;
 640		case LINK_FAILOVER_BEGIN_EVT:
 641			l->state = LINK_FAILINGOVER;
 642			break;
 643		case LINK_FAILURE_EVT:
 644		case LINK_RESET_EVT:
 645		case LINK_ESTABLISH_EVT:
 646		case LINK_FAILOVER_END_EVT:
 647			break;
 648		case LINK_SYNCH_BEGIN_EVT:
 649		case LINK_SYNCH_END_EVT:
 650		default:
 651			goto illegal_evt;
 652		}
 653		break;
 654	case LINK_PEER_RESET:
 655		switch (evt) {
 656		case LINK_RESET_EVT:
 657			l->state = LINK_ESTABLISHING;
 658			break;
 659		case LINK_PEER_RESET_EVT:
 660		case LINK_ESTABLISH_EVT:
 661		case LINK_FAILURE_EVT:
 662			break;
 663		case LINK_SYNCH_BEGIN_EVT:
 664		case LINK_SYNCH_END_EVT:
 665		case LINK_FAILOVER_BEGIN_EVT:
 666		case LINK_FAILOVER_END_EVT:
 667		default:
 668			goto illegal_evt;
 669		}
 670		break;
 671	case LINK_FAILINGOVER:
 672		switch (evt) {
 673		case LINK_FAILOVER_END_EVT:
 674			l->state = LINK_RESET;
 675			break;
 676		case LINK_PEER_RESET_EVT:
 677		case LINK_RESET_EVT:
 678		case LINK_ESTABLISH_EVT:
 679		case LINK_FAILURE_EVT:
 680			break;
 681		case LINK_FAILOVER_BEGIN_EVT:
 682		case LINK_SYNCH_BEGIN_EVT:
 683		case LINK_SYNCH_END_EVT:
 684		default:
 685			goto illegal_evt;
 686		}
 687		break;
 688	case LINK_ESTABLISHING:
 689		switch (evt) {
 690		case LINK_ESTABLISH_EVT:
 691			l->state = LINK_ESTABLISHED;
 692			break;
 693		case LINK_FAILOVER_BEGIN_EVT:
 694			l->state = LINK_FAILINGOVER;
 695			break;
 696		case LINK_RESET_EVT:
 697			l->state = LINK_RESET;
 698			break;
 699		case LINK_FAILURE_EVT:
 700		case LINK_PEER_RESET_EVT:
 701		case LINK_SYNCH_BEGIN_EVT:
 702		case LINK_FAILOVER_END_EVT:
 703			break;
 704		case LINK_SYNCH_END_EVT:
 705		default:
 706			goto illegal_evt;
 707		}
 708		break;
 709	case LINK_ESTABLISHED:
 710		switch (evt) {
 711		case LINK_PEER_RESET_EVT:
 712			l->state = LINK_PEER_RESET;
 713			rc |= TIPC_LINK_DOWN_EVT;
 714			break;
 715		case LINK_FAILURE_EVT:
 716			l->state = LINK_RESETTING;
 717			rc |= TIPC_LINK_DOWN_EVT;
 718			break;
 719		case LINK_RESET_EVT:
 720			l->state = LINK_RESET;
 721			break;
 722		case LINK_ESTABLISH_EVT:
 723		case LINK_SYNCH_END_EVT:
 724			break;
 725		case LINK_SYNCH_BEGIN_EVT:
 726			l->state = LINK_SYNCHING;
 727			break;
 728		case LINK_FAILOVER_BEGIN_EVT:
 729		case LINK_FAILOVER_END_EVT:
 730		default:
 731			goto illegal_evt;
 732		}
 733		break;
 734	case LINK_SYNCHING:
 735		switch (evt) {
 736		case LINK_PEER_RESET_EVT:
 737			l->state = LINK_PEER_RESET;
 738			rc |= TIPC_LINK_DOWN_EVT;
 739			break;
 740		case LINK_FAILURE_EVT:
 741			l->state = LINK_RESETTING;
 742			rc |= TIPC_LINK_DOWN_EVT;
 743			break;
 744		case LINK_RESET_EVT:
 745			l->state = LINK_RESET;
 746			break;
 747		case LINK_ESTABLISH_EVT:
 748		case LINK_SYNCH_BEGIN_EVT:
 749			break;
 750		case LINK_SYNCH_END_EVT:
 751			l->state = LINK_ESTABLISHED;
 752			break;
 753		case LINK_FAILOVER_BEGIN_EVT:
 754		case LINK_FAILOVER_END_EVT:
 755		default:
 756			goto illegal_evt;
 757		}
 758		break;
 759	default:
 760		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
 761	}
 762	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
 763	return rc;
 764illegal_evt:
 765	pr_err("Illegal FSM event %x in state %x on link %s\n",
 766	       evt, l->state, l->name);
 767	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
 768	return rc;
 769}
 770
 771/* link_profile_stats - update statistical profiling of traffic
 772 */
 773static void link_profile_stats(struct tipc_link *l)
 774{
 775	struct sk_buff *skb;
 776	struct tipc_msg *msg;
 777	int length;
 778
 779	/* Update counters used in statistical profiling of send traffic */
 780	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 781	l->stats.queue_sz_counts++;
 782
 783	skb = skb_peek(&l->transmq);
 784	if (!skb)
 785		return;
 786	msg = buf_msg(skb);
 787	length = msg_size(msg);
 788
 789	if (msg_user(msg) == MSG_FRAGMENTER) {
 790		if (msg_type(msg) != FIRST_FRAGMENT)
 791			return;
 792		length = msg_size(msg_inner_hdr(msg));
 793	}
 794	l->stats.msg_lengths_total += length;
 795	l->stats.msg_length_counts++;
 796	if (length <= 64)
 797		l->stats.msg_length_profile[0]++;
 798	else if (length <= 256)
 799		l->stats.msg_length_profile[1]++;
 800	else if (length <= 1024)
 801		l->stats.msg_length_profile[2]++;
 802	else if (length <= 4096)
 803		l->stats.msg_length_profile[3]++;
 804	else if (length <= 16384)
 805		l->stats.msg_length_profile[4]++;
 806	else if (length <= 32768)
 807		l->stats.msg_length_profile[5]++;
 808	else
 809		l->stats.msg_length_profile[6]++;
 810}
 811
 812/**
 813 * tipc_link_too_silent - check if link is "too silent"
 814 * @l: tipc link to be checked
 815 *
 816 * Return: true if the link 'silent_intv_cnt' is about to reach the
 817 * 'abort_limit' value, otherwise false
 818 */
 819bool tipc_link_too_silent(struct tipc_link *l)
 820{
 821	return (l->silent_intv_cnt + 2 > l->abort_limit);
 822}
 823
 824/* tipc_link_timeout - perform periodic task as instructed from node timeout
 825 */
 826int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 827{
 828	int mtyp = 0;
 829	int rc = 0;
 830	bool state = false;
 831	bool probe = false;
 832	bool setup = false;
 833	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
 834	u16 bc_acked = l->bc_rcvlink->acked;
 835	struct tipc_mon_state *mstate = &l->mon_state;
 836
 837	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
 838	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
 839	switch (l->state) {
 840	case LINK_ESTABLISHED:
 841	case LINK_SYNCHING:
 842		mtyp = STATE_MSG;
 843		link_profile_stats(l);
 844		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
 845		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
 846			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 847		state = bc_acked != bc_snt;
 848		state |= l->bc_rcvlink->rcv_unacked;
 849		state |= l->rcv_unacked;
 850		state |= !skb_queue_empty(&l->transmq);
 851		probe = mstate->probing;
 852		probe |= l->silent_intv_cnt;
 853		if (probe || mstate->monitoring)
 854			l->silent_intv_cnt++;
 855		probe |= !skb_queue_empty(&l->deferdq);
 856		if (l->snd_nxt == l->checkpoint) {
 857			tipc_link_update_cwin(l, 0, 0);
 858			probe = true;
 859		}
 860		l->checkpoint = l->snd_nxt;
 861		break;
 862	case LINK_RESET:
 863		setup = l->rst_cnt++ <= 4;
 864		setup |= !(l->rst_cnt % 16);
 865		mtyp = RESET_MSG;
 866		break;
 867	case LINK_ESTABLISHING:
 868		setup = true;
 869		mtyp = ACTIVATE_MSG;
 870		break;
 871	case LINK_PEER_RESET:
 872	case LINK_RESETTING:
 873	case LINK_FAILINGOVER:
 874		break;
 875	default:
 876		break;
 877	}
 878
 879	if (state || probe || setup)
 880		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
 881
 882	return rc;
 883}
 884
 885/**
 886 * link_schedule_user - schedule a message sender for wakeup after congestion
 887 * @l: congested link
 888 * @hdr: header of message that is being sent
 889 * Create pseudo msg to send back to user when congestion abates
 890 */
 891static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
 892{
 893	u32 dnode = tipc_own_addr(l->net);
 894	u32 dport = msg_origport(hdr);
 895	struct sk_buff *skb;
 896
 897	/* Create and schedule wakeup pseudo message */
 898	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 899			      dnode, l->addr, dport, 0, 0);
 900	if (!skb)
 901		return -ENOBUFS;
 902	msg_set_dest_droppable(buf_msg(skb), true);
 903	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
 904	skb_queue_tail(&l->wakeupq, skb);
 905	l->stats.link_congs++;
 906	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
 907	return -ELINKCONG;
 908}
 909
 910/**
 911 * link_prepare_wakeup - prepare users for wakeup after congestion
 912 * @l: congested link
 913 * Wake up a number of waiting users, as permitted by available space
 914 * in the send queue
 915 */
 916static void link_prepare_wakeup(struct tipc_link *l)
 917{
 918	struct sk_buff_head *wakeupq = &l->wakeupq;
 919	struct sk_buff_head *inputq = l->inputq;
 920	struct sk_buff *skb, *tmp;
 921	struct sk_buff_head tmpq;
 922	int avail[5] = {0,};
 923	int imp = 0;
 924
 925	__skb_queue_head_init(&tmpq);
 926
 927	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
 928		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
 929
 930	skb_queue_walk_safe(wakeupq, skb, tmp) {
 931		imp = TIPC_SKB_CB(skb)->chain_imp;
 932		if (avail[imp] <= 0)
 933			continue;
 934		avail[imp]--;
 935		__skb_unlink(skb, wakeupq);
 936		__skb_queue_tail(&tmpq, skb);
 937	}
 938
 939	spin_lock_bh(&inputq->lock);
 940	skb_queue_splice_tail(&tmpq, inputq);
 941	spin_unlock_bh(&inputq->lock);
 942
 943}
 944
 945/**
 946 * tipc_link_set_skb_retransmit_time - set the time at which retransmission of
 947 *                                     the given skb should be next attempted
 948 * @skb: skb to set a future retransmission time for
 949 * @l: link the skb will be transmitted on
 950 */
 951static void tipc_link_set_skb_retransmit_time(struct sk_buff *skb,
 952					      struct tipc_link *l)
 953{
 954	if (link_is_bc_sndlink(l))
 955		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
 956	else
 957		TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
 958}
 959
 960void tipc_link_reset(struct tipc_link *l)
 961{
 962	struct sk_buff_head list;
 963	u32 imp;
 964
 965	__skb_queue_head_init(&list);
 966
 967	l->in_session = false;
 968	/* Force re-synch of peer session number before establishing */
 969	l->peer_session--;
 970	l->session++;
 971	l->mtu = l->advertised_mtu;
 972
 973	spin_lock_bh(&l->wakeupq.lock);
 974	skb_queue_splice_init(&l->wakeupq, &list);
 975	spin_unlock_bh(&l->wakeupq.lock);
 976
 977	spin_lock_bh(&l->inputq->lock);
 978	skb_queue_splice_init(&list, l->inputq);
 979	spin_unlock_bh(&l->inputq->lock);
 980
 981	__skb_queue_purge(&l->transmq);
 982	__skb_queue_purge(&l->deferdq);
 983	__skb_queue_purge(&l->backlogq);
 984	__skb_queue_purge(&l->failover_deferdq);
 985	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
 986		l->backlog[imp].len = 0;
 987		l->backlog[imp].target_bskb = NULL;
 988	}
 989	kfree_skb(l->reasm_buf);
 990	kfree_skb(l->reasm_tnlmsg);
 991	kfree_skb(l->failover_reasm_skb);
 992	l->reasm_buf = NULL;
 993	l->reasm_tnlmsg = NULL;
 994	l->failover_reasm_skb = NULL;
 995	l->rcv_unacked = 0;
 996	l->snd_nxt = 1;
 997	l->rcv_nxt = 1;
 998	l->snd_nxt_state = 1;
 999	l->rcv_nxt_state = 1;
1000	l->acked = 0;
1001	l->last_gap = 0;
1002	kfree(l->last_ga);
1003	l->last_ga = NULL;
1004	l->silent_intv_cnt = 0;
1005	l->rst_cnt = 0;
1006	l->bc_peer_is_up = false;
1007	memset(&l->mon_state, 0, sizeof(l->mon_state));
1008	tipc_link_reset_stats(l);
1009}
1010
1011/**
1012 * tipc_link_xmit(): enqueue buffer list according to queue situation
1013 * @l: link to use
1014 * @list: chain of buffers containing message
1015 * @xmitq: returned list of packets to be sent by caller
1016 *
1017 * Consumes the buffer chain.
1018 * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
1019 * Return: 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
1020 */
1021int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
1022		   struct sk_buff_head *xmitq)
1023{
1024	struct sk_buff_head *backlogq = &l->backlogq;
1025	struct sk_buff_head *transmq = &l->transmq;
1026	struct sk_buff *skb, *_skb;
1027	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1028	u16 ack = l->rcv_nxt - 1;
1029	u16 seqno = l->snd_nxt;
1030	int pkt_cnt = skb_queue_len(list);
1031	unsigned int mss = tipc_link_mss(l);
1032	unsigned int cwin = l->window;
1033	unsigned int mtu = l->mtu;
1034	struct tipc_msg *hdr;
1035	bool new_bundle;
1036	int rc = 0;
1037	int imp;
1038
1039	if (pkt_cnt <= 0)
1040		return 0;
1041
1042	hdr = buf_msg(skb_peek(list));
1043	if (unlikely(msg_size(hdr) > mtu)) {
1044		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1045			skb_queue_len(list), msg_user(hdr),
1046			msg_type(hdr), msg_size(hdr), mtu);
1047		__skb_queue_purge(list);
1048		return -EMSGSIZE;
1049	}
1050
1051	imp = msg_importance(hdr);
1052	/* Allow oversubscription of one data msg per source at congestion */
1053	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1054		if (imp == TIPC_SYSTEM_IMPORTANCE) {
1055			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1056			return -ENOBUFS;
1057		}
1058		rc = link_schedule_user(l, hdr);
1059	}
1060
1061	if (pkt_cnt > 1) {
1062		l->stats.sent_fragmented++;
1063		l->stats.sent_fragments += pkt_cnt;
1064	}
1065
1066	/* Prepare each packet for sending, and add to relevant queue: */
1067	while ((skb = __skb_dequeue(list))) {
1068		if (likely(skb_queue_len(transmq) < cwin)) {
1069			hdr = buf_msg(skb);
1070			msg_set_seqno(hdr, seqno);
1071			msg_set_ack(hdr, ack);
1072			msg_set_bcast_ack(hdr, bc_ack);
1073			_skb = skb_clone(skb, GFP_ATOMIC);
1074			if (!_skb) {
1075				kfree_skb(skb);
1076				__skb_queue_purge(list);
1077				return -ENOBUFS;
1078			}
1079			__skb_queue_tail(transmq, skb);
1080			tipc_link_set_skb_retransmit_time(skb, l);
1081			__skb_queue_tail(xmitq, _skb);
1082			TIPC_SKB_CB(skb)->ackers = l->ackers;
1083			l->rcv_unacked = 0;
1084			l->stats.sent_pkts++;
1085			seqno++;
1086			continue;
1087		}
1088		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1089					mss, l->addr, &new_bundle)) {
1090			if (skb) {
1091				/* Keep a ref. to the skb for next try */
1092				l->backlog[imp].target_bskb = skb;
1093				l->backlog[imp].len++;
1094				__skb_queue_tail(backlogq, skb);
1095			} else {
1096				if (new_bundle) {
1097					l->stats.sent_bundles++;
1098					l->stats.sent_bundled++;
1099				}
1100				l->stats.sent_bundled++;
1101			}
1102			continue;
1103		}
1104		l->backlog[imp].target_bskb = NULL;
1105		l->backlog[imp].len += (1 + skb_queue_len(list));
1106		__skb_queue_tail(backlogq, skb);
1107		skb_queue_splice_tail_init(list, backlogq);
1108	}
1109	l->snd_nxt = seqno;
1110	return rc;
1111}
1112
1113static void tipc_link_update_cwin(struct tipc_link *l, int released,
1114				  bool retransmitted)
1115{
1116	int bklog_len = skb_queue_len(&l->backlogq);
1117	struct sk_buff_head *txq = &l->transmq;
1118	int txq_len = skb_queue_len(txq);
1119	u16 cwin = l->window;
1120
1121	/* Enter fast recovery */
1122	if (unlikely(retransmitted)) {
1123		l->ssthresh = max_t(u16, l->window / 2, 300);
1124		l->window = min_t(u16, l->ssthresh, l->window);
1125		return;
1126	}
1127	/* Enter slow start */
1128	if (unlikely(!released)) {
1129		l->ssthresh = max_t(u16, l->window / 2, 300);
1130		l->window = l->min_win;
1131		return;
1132	}
1133	/* Don't increase window if no pressure on the transmit queue */
1134	if (txq_len + bklog_len < cwin)
1135		return;
1136
1137	/* Don't increase window if there are holes the transmit queue */
1138	if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1139		return;
1140
1141	l->cong_acks += released;
1142
1143	/* Slow start  */
1144	if (cwin <= l->ssthresh) {
1145		l->window = min_t(u16, cwin + released, l->max_win);
1146		return;
1147	}
1148	/* Congestion avoidance */
1149	if (l->cong_acks < cwin)
1150		return;
1151	l->window = min_t(u16, ++cwin, l->max_win);
1152	l->cong_acks = 0;
1153}
1154
1155static void tipc_link_advance_backlog(struct tipc_link *l,
1156				      struct sk_buff_head *xmitq)
1157{
1158	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1159	struct sk_buff_head *txq = &l->transmq;
1160	struct sk_buff *skb, *_skb;
1161	u16 ack = l->rcv_nxt - 1;
1162	u16 seqno = l->snd_nxt;
1163	struct tipc_msg *hdr;
1164	u16 cwin = l->window;
1165	u32 imp;
1166
1167	while (skb_queue_len(txq) < cwin) {
1168		skb = skb_peek(&l->backlogq);
1169		if (!skb)
1170			break;
1171		_skb = skb_clone(skb, GFP_ATOMIC);
1172		if (!_skb)
1173			break;
1174		__skb_dequeue(&l->backlogq);
1175		hdr = buf_msg(skb);
1176		imp = msg_importance(hdr);
1177		l->backlog[imp].len--;
1178		if (unlikely(skb == l->backlog[imp].target_bskb))
1179			l->backlog[imp].target_bskb = NULL;
1180		__skb_queue_tail(&l->transmq, skb);
1181		tipc_link_set_skb_retransmit_time(skb, l);
1182
1183		__skb_queue_tail(xmitq, _skb);
1184		TIPC_SKB_CB(skb)->ackers = l->ackers;
1185		msg_set_seqno(hdr, seqno);
1186		msg_set_ack(hdr, ack);
1187		msg_set_bcast_ack(hdr, bc_ack);
1188		l->rcv_unacked = 0;
1189		l->stats.sent_pkts++;
1190		seqno++;
1191	}
1192	l->snd_nxt = seqno;
1193}
1194
1195/**
1196 * link_retransmit_failure() - Detect repeated retransmit failures
1197 * @l: tipc link sender
1198 * @r: tipc link receiver (= l in case of unicast)
1199 * @rc: returned code
1200 *
1201 * Return: true if the repeated retransmit failures happens, otherwise
1202 * false
1203 */
1204static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1205				    int *rc)
1206{
1207	struct sk_buff *skb = skb_peek(&l->transmq);
1208	struct tipc_msg *hdr;
1209
1210	if (!skb)
1211		return false;
1212
1213	if (!TIPC_SKB_CB(skb)->retr_cnt)
1214		return false;
1215
1216	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1217			msecs_to_jiffies(r->tolerance * 10)))
1218		return false;
1219
1220	hdr = buf_msg(skb);
1221	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1222		return false;
1223
1224	pr_warn("Retransmission failure on link <%s>\n", l->name);
1225	link_print(l, "State of link ");
1226	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1227		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1228	pr_info("sqno %u, prev: %x, dest: %x\n",
1229		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1230	pr_info("retr_stamp %d, retr_cnt %d\n",
1231		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1232		TIPC_SKB_CB(skb)->retr_cnt);
1233
1234	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1235	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1236	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1237
1238	if (link_is_bc_sndlink(l)) {
1239		r->state = LINK_RESET;
1240		*rc |= TIPC_LINK_DOWN_EVT;
1241	} else {
1242		*rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1243	}
1244
1245	return true;
1246}
1247
1248/* tipc_data_input - deliver data and name distr msgs to upper layer
1249 *
1250 * Consumes buffer if message is of right type
1251 * Node lock must be held
1252 */
1253static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1254			    struct sk_buff_head *inputq)
1255{
1256	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1257	struct tipc_msg *hdr = buf_msg(skb);
1258
1259	switch (msg_user(hdr)) {
1260	case TIPC_LOW_IMPORTANCE:
1261	case TIPC_MEDIUM_IMPORTANCE:
1262	case TIPC_HIGH_IMPORTANCE:
1263	case TIPC_CRITICAL_IMPORTANCE:
1264		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1265			skb_queue_tail(mc_inputq, skb);
1266			return true;
1267		}
1268		fallthrough;
1269	case CONN_MANAGER:
1270		skb_queue_tail(inputq, skb);
1271		return true;
1272	case GROUP_PROTOCOL:
1273		skb_queue_tail(mc_inputq, skb);
1274		return true;
1275	case NAME_DISTRIBUTOR:
1276		l->bc_rcvlink->state = LINK_ESTABLISHED;
1277		skb_queue_tail(l->namedq, skb);
1278		return true;
1279	case MSG_BUNDLER:
1280	case TUNNEL_PROTOCOL:
1281	case MSG_FRAGMENTER:
1282	case BCAST_PROTOCOL:
1283		return false;
1284#ifdef CONFIG_TIPC_CRYPTO
1285	case MSG_CRYPTO:
1286		if (sysctl_tipc_key_exchange_enabled &&
1287		    TIPC_SKB_CB(skb)->decrypted) {
1288			tipc_crypto_msg_rcv(l->net, skb);
1289			return true;
1290		}
1291		fallthrough;
1292#endif
1293	default:
1294		pr_warn("Dropping received illegal msg type\n");
1295		kfree_skb(skb);
1296		return true;
1297	}
1298}
1299
1300/* tipc_link_input - process packet that has passed link protocol check
1301 *
1302 * Consumes buffer
1303 */
1304static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1305			   struct sk_buff_head *inputq,
1306			   struct sk_buff **reasm_skb)
1307{
1308	struct tipc_msg *hdr = buf_msg(skb);
1309	struct sk_buff *iskb;
1310	struct sk_buff_head tmpq;
1311	int usr = msg_user(hdr);
1312	int pos = 0;
1313
1314	if (usr == MSG_BUNDLER) {
1315		skb_queue_head_init(&tmpq);
1316		l->stats.recv_bundles++;
1317		l->stats.recv_bundled += msg_msgcnt(hdr);
1318		while (tipc_msg_extract(skb, &iskb, &pos))
1319			tipc_data_input(l, iskb, &tmpq);
1320		tipc_skb_queue_splice_tail(&tmpq, inputq);
1321		return 0;
1322	} else if (usr == MSG_FRAGMENTER) {
1323		l->stats.recv_fragments++;
1324		if (tipc_buf_append(reasm_skb, &skb)) {
1325			l->stats.recv_fragmented++;
1326			tipc_data_input(l, skb, inputq);
1327		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1328			pr_warn_ratelimited("Unable to build fragment list\n");
1329			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1330		}
1331		return 0;
1332	} else if (usr == BCAST_PROTOCOL) {
1333		tipc_bcast_lock(l->net);
1334		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1335		tipc_bcast_unlock(l->net);
1336	}
1337
1338	kfree_skb(skb);
1339	return 0;
1340}
1341
1342/* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1343 *			 inner message along with the ones in the old link's
1344 *			 deferdq
1345 * @l: tunnel link
1346 * @skb: TUNNEL_PROTOCOL message
1347 * @inputq: queue to put messages ready for delivery
1348 */
1349static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1350			     struct sk_buff_head *inputq)
1351{
1352	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1353	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1354	struct sk_buff_head *fdefq = &l->failover_deferdq;
1355	struct tipc_msg *hdr = buf_msg(skb);
1356	struct sk_buff *iskb;
1357	int ipos = 0;
1358	int rc = 0;
1359	u16 seqno;
1360
1361	if (msg_type(hdr) == SYNCH_MSG) {
1362		kfree_skb(skb);
1363		return 0;
1364	}
1365
1366	/* Not a fragment? */
1367	if (likely(!msg_nof_fragms(hdr))) {
1368		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1369			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1370					    skb_queue_len(fdefq));
1371			return 0;
1372		}
1373		kfree_skb(skb);
1374	} else {
1375		/* Set fragment type for buf_append */
1376		if (msg_fragm_no(hdr) == 1)
1377			msg_set_type(hdr, FIRST_FRAGMENT);
1378		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1379			msg_set_type(hdr, FRAGMENT);
1380		else
1381			msg_set_type(hdr, LAST_FRAGMENT);
1382
1383		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1384			/* Successful but non-complete reassembly? */
1385			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1386				return 0;
1387			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1388			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1389		}
1390		iskb = skb;
1391	}
1392
1393	do {
1394		seqno = buf_seqno(iskb);
1395		if (unlikely(less(seqno, l->drop_point))) {
1396			kfree_skb(iskb);
1397			continue;
1398		}
1399		if (unlikely(seqno != l->drop_point)) {
1400			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
1401			continue;
1402		}
1403
1404		l->drop_point++;
1405		if (!tipc_data_input(l, iskb, inputq))
1406			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1407		if (unlikely(rc))
1408			break;
1409	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1410
1411	return rc;
1412}
1413
1414/**
1415 * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1416 * @ga: returned pointer to the Gap ACK blocks if any
1417 * @l: the tipc link
1418 * @hdr: the PROTOCOL/STATE_MSG header
1419 * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1420 *
1421 * Return: the total Gap ACK blocks size
1422 */
1423u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1424			  struct tipc_msg *hdr, bool uc)
1425{
1426	struct tipc_gap_ack_blks *p;
1427	u16 sz = 0;
1428
1429	/* Does peer support the Gap ACK blocks feature? */
1430	if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1431		p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1432		sz = ntohs(p->len);
1433		/* Sanity check */
1434		if (sz == struct_size(p, gacks, size_add(p->ugack_cnt, p->bgack_cnt))) {
1435			/* Good, check if the desired type exists */
1436			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1437				goto ok;
1438		/* Backward compatible: peer might not support bc, but uc? */
1439		} else if (uc && sz == struct_size(p, gacks, p->ugack_cnt)) {
1440			if (p->ugack_cnt) {
1441				p->bgack_cnt = 0;
1442				goto ok;
1443			}
1444		}
1445	}
1446	/* Other cases: ignore! */
1447	p = NULL;
1448
1449ok:
1450	*ga = p;
1451	return sz;
1452}
1453
1454static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1455				    struct tipc_link *l, u8 start_index)
1456{
1457	struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1458	struct sk_buff *skb = skb_peek(&l->deferdq);
1459	u16 expect, seqno = 0;
1460	u8 n = 0;
1461
1462	if (!skb)
1463		return 0;
1464
1465	expect = buf_seqno(skb);
1466	skb_queue_walk(&l->deferdq, skb) {
1467		seqno = buf_seqno(skb);
1468		if (unlikely(more(seqno, expect))) {
1469			gacks[n].ack = htons(expect - 1);
1470			gacks[n].gap = htons(seqno - expect);
1471			if (++n >= MAX_GAP_ACK_BLKS / 2) {
1472				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1473						    l->name, n,
1474						    skb_queue_len(&l->deferdq));
1475				return n;
1476			}
1477		} else if (unlikely(less(seqno, expect))) {
1478			pr_warn("Unexpected skb in deferdq!\n");
1479			continue;
1480		}
1481		expect = seqno + 1;
1482	}
1483
1484	/* last block */
1485	gacks[n].ack = htons(seqno);
1486	gacks[n].gap = 0;
1487	n++;
1488	return n;
1489}
1490
1491/* tipc_build_gap_ack_blks - build Gap ACK blocks
1492 * @l: tipc unicast link
1493 * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1494 *
1495 * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1496 * links of a certain peer, the buffer after built has the network data format
1497 * as found at the struct tipc_gap_ack_blks definition.
1498 *
1499 * returns the actual allocated memory size
1500 */
1501static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1502{
1503	struct tipc_link *bcl = l->bc_rcvlink;
1504	struct tipc_gap_ack_blks *ga;
1505	u16 len;
1506
1507	ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1508
1509	/* Start with broadcast link first */
1510	tipc_bcast_lock(bcl->net);
1511	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1512	msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1513	ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1514	tipc_bcast_unlock(bcl->net);
1515
1516	/* Now for unicast link, but an explicit NACK only (???) */
1517	ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1518			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1519
1520	/* Total len */
1521	len = struct_size(ga, gacks, size_add(ga->bgack_cnt, ga->ugack_cnt));
1522	ga->len = htons(len);
1523	return len;
1524}
1525
1526/* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1527 *			       acked packets, also doing retransmissions if
1528 *			       gaps found
1529 * @l: tipc link with transmq queue to be advanced
1530 * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1531 * @acked: seqno of last packet acked by peer without any gaps before
1532 * @gap: # of gap packets
1533 * @ga: buffer pointer to Gap ACK blocks from peer
1534 * @xmitq: queue for accumulating the retransmitted packets if any
1535 * @retransmitted: returned boolean value if a retransmission is really issued
1536 * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1537 *      happens (- unlikely case)
1538 *
1539 * Return: the number of packets released from the link transmq
1540 */
1541static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1542				     u16 acked, u16 gap,
1543				     struct tipc_gap_ack_blks *ga,
1544				     struct sk_buff_head *xmitq,
1545				     bool *retransmitted, int *rc)
1546{
1547	struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1548	struct tipc_gap_ack *gacks = NULL;
1549	struct sk_buff *skb, *_skb, *tmp;
1550	struct tipc_msg *hdr;
1551	u32 qlen = skb_queue_len(&l->transmq);
1552	u16 nacked = acked, ngap = gap, gack_cnt = 0;
1553	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1554	u16 ack = l->rcv_nxt - 1;
1555	u16 seqno, n = 0;
1556	u16 end = r->acked, start = end, offset = r->last_gap;
1557	u16 si = (last_ga) ? last_ga->start_index : 0;
1558	bool is_uc = !link_is_bc_sndlink(l);
1559	bool bc_has_acked = false;
1560
1561	trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1562
1563	/* Determine Gap ACK blocks if any for the particular link */
1564	if (ga && is_uc) {
1565		/* Get the Gap ACKs, uc part */
1566		gack_cnt = ga->ugack_cnt;
1567		gacks = &ga->gacks[ga->bgack_cnt];
1568	} else if (ga) {
1569		/* Copy the Gap ACKs, bc part, for later renewal if needed */
1570		this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),
1571				  GFP_ATOMIC);
1572		if (likely(this_ga)) {
1573			this_ga->start_index = 0;
1574			/* Start with the bc Gap ACKs */
1575			gack_cnt = this_ga->bgack_cnt;
1576			gacks = &this_ga->gacks[0];
1577		} else {
1578			/* Hmm, we can get in trouble..., simply ignore it */
1579			pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1580		}
1581	}
1582
1583	/* Advance the link transmq */
1584	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1585		seqno = buf_seqno(skb);
1586
1587next_gap_ack:
1588		if (less_eq(seqno, nacked)) {
1589			if (is_uc)
1590				goto release;
1591			/* Skip packets peer has already acked */
1592			if (!more(seqno, r->acked))
1593				continue;
1594			/* Get the next of last Gap ACK blocks */
1595			while (more(seqno, end)) {
1596				if (!last_ga || si >= last_ga->bgack_cnt)
1597					break;
1598				start = end + offset + 1;
1599				end = ntohs(last_ga->gacks[si].ack);
1600				offset = ntohs(last_ga->gacks[si].gap);
1601				si++;
1602				WARN_ONCE(more(start, end) ||
1603					  (!offset &&
1604					   si < last_ga->bgack_cnt) ||
1605					  si > MAX_GAP_ACK_BLKS,
1606					  "Corrupted Gap ACK: %d %d %d %d %d\n",
1607					  start, end, offset, si,
1608					  last_ga->bgack_cnt);
1609			}
1610			/* Check against the last Gap ACK block */
1611			if (tipc_in_range(seqno, start, end))
1612				continue;
1613			/* Update/release the packet peer is acking */
1614			bc_has_acked = true;
1615			if (--TIPC_SKB_CB(skb)->ackers)
1616				continue;
1617release:
1618			/* release skb */
1619			__skb_unlink(skb, &l->transmq);
1620			kfree_skb(skb);
1621		} else if (less_eq(seqno, nacked + ngap)) {
1622			/* First gap: check if repeated retrans failures? */
1623			if (unlikely(seqno == acked + 1 &&
1624				     link_retransmit_failure(l, r, rc))) {
1625				/* Ignore this bc Gap ACKs if any */
1626				kfree(this_ga);
1627				this_ga = NULL;
1628				break;
1629			}
1630			/* retransmit skb if unrestricted*/
1631			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1632				continue;
1633			tipc_link_set_skb_retransmit_time(skb, l);
1634			_skb = pskb_copy(skb, GFP_ATOMIC);
1635			if (!_skb)
1636				continue;
1637			hdr = buf_msg(_skb);
1638			msg_set_ack(hdr, ack);
1639			msg_set_bcast_ack(hdr, bc_ack);
1640			_skb->priority = TC_PRIO_CONTROL;
1641			__skb_queue_tail(xmitq, _skb);
1642			l->stats.retransmitted++;
1643			if (!is_uc)
1644				r->stats.retransmitted++;
1645			*retransmitted = true;
1646			/* Increase actual retrans counter & mark first time */
1647			if (!TIPC_SKB_CB(skb)->retr_cnt++)
1648				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1649		} else {
1650			/* retry with Gap ACK blocks if any */
1651			if (n >= gack_cnt)
1652				break;
1653			nacked = ntohs(gacks[n].ack);
1654			ngap = ntohs(gacks[n].gap);
1655			n++;
1656			goto next_gap_ack;
1657		}
1658	}
1659
1660	/* Renew last Gap ACK blocks for bc if needed */
1661	if (bc_has_acked) {
1662		if (this_ga) {
1663			kfree(last_ga);
1664			r->last_ga = this_ga;
1665			r->last_gap = gap;
1666		} else if (last_ga) {
1667			if (less(acked, start)) {
1668				si--;
1669				offset = start - acked - 1;
1670			} else if (less(acked, end)) {
1671				acked = end;
1672			}
1673			if (si < last_ga->bgack_cnt) {
1674				last_ga->start_index = si;
1675				r->last_gap = offset;
1676			} else {
1677				kfree(last_ga);
1678				r->last_ga = NULL;
1679				r->last_gap = 0;
1680			}
1681		} else {
1682			r->last_gap = 0;
1683		}
1684		r->acked = acked;
1685	} else {
1686		kfree(this_ga);
1687	}
1688
1689	return qlen - skb_queue_len(&l->transmq);
1690}
1691
1692/* tipc_link_build_state_msg: prepare link state message for transmission
1693 *
1694 * Note that sending of broadcast ack is coordinated among nodes, to reduce
1695 * risk of ack storms towards the sender
1696 */
1697int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1698{
1699	if (!l)
1700		return 0;
1701
1702	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1703	if (link_is_bc_rcvlink(l)) {
1704		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1705			return 0;
1706		l->rcv_unacked = 0;
1707
1708		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1709		l->snd_nxt = l->rcv_nxt;
1710		return TIPC_LINK_SND_STATE;
1711	}
1712	/* Unicast ACK */
1713	l->rcv_unacked = 0;
1714	l->stats.sent_acks++;
1715	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1716	return 0;
1717}
1718
1719/* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1720 */
1721void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1722{
1723	int mtyp = RESET_MSG;
1724	struct sk_buff *skb;
1725
1726	if (l->state == LINK_ESTABLISHING)
1727		mtyp = ACTIVATE_MSG;
1728
1729	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1730
1731	/* Inform peer that this endpoint is going down if applicable */
1732	skb = skb_peek_tail(xmitq);
1733	if (skb && (l->state == LINK_RESET))
1734		msg_set_peer_stopping(buf_msg(skb), 1);
1735}
1736
1737/* tipc_link_build_nack_msg: prepare link nack message for transmission
1738 * Note that sending of broadcast NACK is coordinated among nodes, to
1739 * reduce the risk of NACK storms towards the sender
1740 */
1741static int tipc_link_build_nack_msg(struct tipc_link *l,
1742				    struct sk_buff_head *xmitq)
1743{
1744	u32 def_cnt = ++l->stats.deferred_recv;
1745	struct sk_buff_head *dfq = &l->deferdq;
1746	u32 defq_len = skb_queue_len(dfq);
1747	int match1, match2;
1748
1749	if (link_is_bc_rcvlink(l)) {
1750		match1 = def_cnt & 0xf;
1751		match2 = tipc_own_addr(l->net) & 0xf;
1752		if (match1 == match2)
1753			return TIPC_LINK_SND_STATE;
1754		return 0;
1755	}
1756
1757	if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1758		u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1759
1760		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1761					  rcvgap, 0, 0, xmitq);
1762	}
1763	return 0;
1764}
1765
1766/* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1767 * @l: the link that should handle the message
1768 * @skb: TIPC packet
1769 * @xmitq: queue to place packets to be sent after this call
1770 */
1771int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1772		  struct sk_buff_head *xmitq)
1773{
1774	struct sk_buff_head *defq = &l->deferdq;
1775	struct tipc_msg *hdr = buf_msg(skb);
1776	u16 seqno, rcv_nxt, win_lim;
1777	int released = 0;
1778	int rc = 0;
1779
1780	/* Verify and update link state */
1781	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1782		return tipc_link_proto_rcv(l, skb, xmitq);
1783
1784	/* Don't send probe at next timeout expiration */
1785	l->silent_intv_cnt = 0;
1786
1787	do {
1788		hdr = buf_msg(skb);
1789		seqno = msg_seqno(hdr);
1790		rcv_nxt = l->rcv_nxt;
1791		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1792
1793		if (unlikely(!link_is_up(l))) {
1794			if (l->state == LINK_ESTABLISHING)
1795				rc = TIPC_LINK_UP_EVT;
1796			kfree_skb(skb);
1797			break;
1798		}
1799
1800		/* Drop if outside receive window */
1801		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1802			l->stats.duplicates++;
1803			kfree_skb(skb);
1804			break;
1805		}
1806		released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1807						      NULL, NULL, NULL, NULL);
1808
1809		/* Defer delivery if sequence gap */
1810		if (unlikely(seqno != rcv_nxt)) {
1811			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1812				l->stats.duplicates++;
1813			rc |= tipc_link_build_nack_msg(l, xmitq);
1814			break;
1815		}
1816
1817		/* Deliver packet */
1818		l->rcv_nxt++;
1819		l->stats.recv_pkts++;
1820
1821		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1822			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1823		else if (!tipc_data_input(l, skb, l->inputq))
1824			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1825		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1826			rc |= tipc_link_build_state_msg(l, xmitq);
1827		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1828			break;
1829	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1830
1831	/* Forward queues and wake up waiting users */
1832	if (released) {
1833		tipc_link_update_cwin(l, released, 0);
1834		tipc_link_advance_backlog(l, xmitq);
1835		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1836			link_prepare_wakeup(l);
1837	}
1838	return rc;
1839}
1840
1841static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1842				      bool probe_reply, u16 rcvgap,
1843				      int tolerance, int priority,
1844				      struct sk_buff_head *xmitq)
1845{
1846	struct tipc_mon_state *mstate = &l->mon_state;
1847	struct sk_buff_head *dfq = &l->deferdq;
1848	struct tipc_link *bcl = l->bc_rcvlink;
1849	struct tipc_msg *hdr;
1850	struct sk_buff *skb;
1851	bool node_up = link_is_up(bcl);
1852	u16 glen = 0, bc_rcvgap = 0;
1853	int dlen = 0;
1854	void *data;
1855
1856	/* Don't send protocol message during reset or link failover */
1857	if (tipc_link_is_blocked(l))
1858		return;
1859
1860	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1861		return;
1862
1863	if ((probe || probe_reply) && !skb_queue_empty(dfq))
1864		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1865
1866	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1867			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1868			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
1869	if (!skb)
1870		return;
1871
1872	hdr = buf_msg(skb);
1873	data = msg_data(hdr);
1874	msg_set_session(hdr, l->session);
1875	msg_set_bearer_id(hdr, l->bearer_id);
1876	msg_set_net_plane(hdr, l->net_plane);
1877	msg_set_next_sent(hdr, l->snd_nxt);
1878	msg_set_ack(hdr, l->rcv_nxt - 1);
1879	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1880	msg_set_bc_ack_invalid(hdr, !node_up);
1881	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1882	msg_set_link_tolerance(hdr, tolerance);
1883	msg_set_linkprio(hdr, priority);
1884	msg_set_redundant_link(hdr, node_up);
1885	msg_set_seq_gap(hdr, 0);
1886	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1887
1888	if (mtyp == STATE_MSG) {
1889		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1890			msg_set_seqno(hdr, l->snd_nxt_state++);
1891		msg_set_seq_gap(hdr, rcvgap);
1892		bc_rcvgap = link_bc_rcv_gap(bcl);
1893		msg_set_bc_gap(hdr, bc_rcvgap);
1894		msg_set_probe(hdr, probe);
1895		msg_set_is_keepalive(hdr, probe || probe_reply);
1896		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1897			glen = tipc_build_gap_ack_blks(l, hdr);
1898		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1899		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1900		skb_trim(skb, INT_H_SIZE + glen + dlen);
1901		l->stats.sent_states++;
1902		l->rcv_unacked = 0;
1903	} else {
1904		/* RESET_MSG or ACTIVATE_MSG */
1905		if (mtyp == ACTIVATE_MSG) {
1906			msg_set_dest_session_valid(hdr, 1);
1907			msg_set_dest_session(hdr, l->peer_session);
1908		}
1909		msg_set_max_pkt(hdr, l->advertised_mtu);
1910		strcpy(data, l->if_name);
1911		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1912		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1913	}
1914	if (probe)
1915		l->stats.sent_probes++;
1916	if (rcvgap)
1917		l->stats.sent_nacks++;
1918	if (bc_rcvgap)
1919		bcl->stats.sent_nacks++;
1920	skb->priority = TC_PRIO_CONTROL;
1921	__skb_queue_tail(xmitq, skb);
1922	trace_tipc_proto_build(skb, false, l->name);
1923}
1924
1925void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1926				    struct sk_buff_head *xmitq)
1927{
1928	u32 onode = tipc_own_addr(l->net);
1929	struct tipc_msg *hdr, *ihdr;
1930	struct sk_buff_head tnlq;
1931	struct sk_buff *skb;
1932	u32 dnode = l->addr;
1933
1934	__skb_queue_head_init(&tnlq);
1935	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1936			      INT_H_SIZE, BASIC_H_SIZE,
1937			      dnode, onode, 0, 0, 0);
1938	if (!skb) {
1939		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1940		return;
1941	}
1942
1943	hdr = buf_msg(skb);
1944	msg_set_msgcnt(hdr, 1);
1945	msg_set_bearer_id(hdr, l->peer_bearer_id);
1946
1947	ihdr = (struct tipc_msg *)msg_data(hdr);
1948	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1949		      BASIC_H_SIZE, dnode);
1950	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1951	__skb_queue_tail(&tnlq, skb);
1952	tipc_link_xmit(l, &tnlq, xmitq);
1953}
1954
1955/* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1956 * with contents of the link's transmit and backlog queues.
1957 */
1958void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1959			   int mtyp, struct sk_buff_head *xmitq)
1960{
1961	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1962	struct sk_buff *skb, *tnlskb;
1963	struct tipc_msg *hdr, tnlhdr;
1964	struct sk_buff_head *queue = &l->transmq;
1965	struct sk_buff_head tmpxq, tnlq, frags;
1966	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1967	bool pktcnt_need_update = false;
1968	u16 syncpt;
1969	int rc;
1970
1971	if (!tnl)
1972		return;
1973
1974	__skb_queue_head_init(&tnlq);
1975	/* Link Synching:
1976	 * From now on, send only one single ("dummy") SYNCH message
1977	 * to peer. The SYNCH message does not contain any data, just
1978	 * a header conveying the synch point to the peer.
1979	 */
1980	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1981		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1982					 INT_H_SIZE, 0, l->addr,
1983					 tipc_own_addr(l->net),
1984					 0, 0, 0);
1985		if (!tnlskb) {
1986			pr_warn("%sunable to create dummy SYNCH_MSG\n",
1987				link_co_err);
1988			return;
1989		}
1990
1991		hdr = buf_msg(tnlskb);
1992		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
1993		msg_set_syncpt(hdr, syncpt);
1994		msg_set_bearer_id(hdr, l->peer_bearer_id);
1995		__skb_queue_tail(&tnlq, tnlskb);
1996		tipc_link_xmit(tnl, &tnlq, xmitq);
1997		return;
1998	}
1999
2000	__skb_queue_head_init(&tmpxq);
2001	__skb_queue_head_init(&frags);
2002	/* At least one packet required for safe algorithm => add dummy */
2003	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
2004			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
2005			      0, 0, TIPC_ERR_NO_PORT);
2006	if (!skb) {
2007		pr_warn("%sunable to create tunnel packet\n", link_co_err);
2008		return;
2009	}
2010	__skb_queue_tail(&tnlq, skb);
2011	tipc_link_xmit(l, &tnlq, &tmpxq);
2012	__skb_queue_purge(&tmpxq);
2013
2014	/* Initialize reusable tunnel packet header */
2015	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
2016		      mtyp, INT_H_SIZE, l->addr);
2017	if (mtyp == SYNCH_MSG)
2018		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
2019	else
2020		pktcnt = skb_queue_len(&l->transmq);
2021	pktcnt += skb_queue_len(&l->backlogq);
2022	msg_set_msgcnt(&tnlhdr, pktcnt);
2023	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
2024tnl:
2025	/* Wrap each packet into a tunnel packet */
2026	skb_queue_walk(queue, skb) {
2027		hdr = buf_msg(skb);
2028		if (queue == &l->backlogq)
2029			msg_set_seqno(hdr, seqno++);
2030		pktlen = msg_size(hdr);
2031
2032		/* Tunnel link MTU is not large enough? This could be
2033		 * due to:
2034		 * 1) Link MTU has just changed or set differently;
2035		 * 2) Or FAILOVER on the top of a SYNCH message
2036		 *
2037		 * The 2nd case should not happen if peer supports
2038		 * TIPC_TUNNEL_ENHANCED
2039		 */
2040		if (pktlen > tnl->mtu - INT_H_SIZE) {
2041			if (mtyp == FAILOVER_MSG &&
2042			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
2043				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
2044						       &frags);
2045				if (rc) {
2046					pr_warn("%sunable to frag msg: rc %d\n",
2047						link_co_err, rc);
2048					return;
2049				}
2050				pktcnt += skb_queue_len(&frags) - 1;
2051				pktcnt_need_update = true;
2052				skb_queue_splice_tail_init(&frags, &tnlq);
2053				continue;
2054			}
2055			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2056			 * => Just warn it and return!
2057			 */
2058			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2059					    link_co_err, msg_user(hdr),
2060					    msg_type(hdr), msg_size(hdr));
2061			return;
2062		}
2063
2064		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2065		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2066		if (!tnlskb) {
2067			pr_warn("%sunable to send packet\n", link_co_err);
2068			return;
2069		}
2070		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2071		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2072		__skb_queue_tail(&tnlq, tnlskb);
2073	}
2074	if (queue != &l->backlogq) {
2075		queue = &l->backlogq;
2076		goto tnl;
2077	}
2078
2079	if (pktcnt_need_update)
2080		skb_queue_walk(&tnlq, skb) {
2081			hdr = buf_msg(skb);
2082			msg_set_msgcnt(hdr, pktcnt);
2083		}
2084
2085	tipc_link_xmit(tnl, &tnlq, xmitq);
2086
2087	if (mtyp == FAILOVER_MSG) {
2088		tnl->drop_point = l->rcv_nxt;
2089		tnl->failover_reasm_skb = l->reasm_buf;
2090		l->reasm_buf = NULL;
2091
2092		/* Failover the link's deferdq */
2093		if (unlikely(!skb_queue_empty(fdefq))) {
2094			pr_warn("Link failover deferdq not empty: %d!\n",
2095				skb_queue_len(fdefq));
2096			__skb_queue_purge(fdefq);
2097		}
2098		skb_queue_splice_init(&l->deferdq, fdefq);
2099	}
2100}
2101
2102/**
2103 * tipc_link_failover_prepare() - prepare tnl for link failover
2104 *
2105 * This is a special version of the precursor - tipc_link_tnl_prepare(),
2106 * see the tipc_node_link_failover() for details
2107 *
2108 * @l: failover link
2109 * @tnl: tunnel link
2110 * @xmitq: queue for messages to be xmited
2111 */
2112void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2113				struct sk_buff_head *xmitq)
2114{
2115	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2116
2117	tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2118
2119	/* This failover link endpoint was never established before,
2120	 * so it has not received anything from peer.
2121	 * Otherwise, it must be a normal failover situation or the
2122	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2123	 * would have to start over from scratch instead.
2124	 */
2125	tnl->drop_point = 1;
2126	tnl->failover_reasm_skb = NULL;
2127
2128	/* Initiate the link's failover deferdq */
2129	if (unlikely(!skb_queue_empty(fdefq))) {
2130		pr_warn("Link failover deferdq not empty: %d!\n",
2131			skb_queue_len(fdefq));
2132		__skb_queue_purge(fdefq);
2133	}
2134}
2135
2136/* tipc_link_validate_msg(): validate message against current link state
2137 * Returns true if message should be accepted, otherwise false
2138 */
2139bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2140{
2141	u16 curr_session = l->peer_session;
2142	u16 session = msg_session(hdr);
2143	int mtyp = msg_type(hdr);
2144
2145	if (msg_user(hdr) != LINK_PROTOCOL)
2146		return true;
2147
2148	switch (mtyp) {
2149	case RESET_MSG:
2150		if (!l->in_session)
2151			return true;
2152		/* Accept only RESET with new session number */
2153		return more(session, curr_session);
2154	case ACTIVATE_MSG:
2155		if (!l->in_session)
2156			return true;
2157		/* Accept only ACTIVATE with new or current session number */
2158		return !less(session, curr_session);
2159	case STATE_MSG:
2160		/* Accept only STATE with current session number */
2161		if (!l->in_session)
2162			return false;
2163		if (session != curr_session)
2164			return false;
2165		/* Extra sanity check */
2166		if (!link_is_up(l) && msg_ack(hdr))
2167			return false;
2168		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2169			return true;
2170		/* Accept only STATE with new sequence number */
2171		return !less(msg_seqno(hdr), l->rcv_nxt_state);
2172	default:
2173		return false;
2174	}
2175}
2176
2177/* tipc_link_proto_rcv(): receive link level protocol message :
2178 * Note that network plane id propagates through the network, and may
2179 * change at any time. The node with lowest numerical id determines
2180 * network plane
2181 */
2182static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2183			       struct sk_buff_head *xmitq)
2184{
2185	struct tipc_msg *hdr = buf_msg(skb);
2186	struct tipc_gap_ack_blks *ga = NULL;
2187	bool reply = msg_probe(hdr), retransmitted = false;
2188	u32 dlen = msg_data_sz(hdr), glen = 0, msg_max;
2189	u16 peers_snd_nxt =  msg_next_sent(hdr);
2190	u16 peers_tol = msg_link_tolerance(hdr);
2191	u16 peers_prio = msg_linkprio(hdr);
2192	u16 gap = msg_seq_gap(hdr);
2193	u16 ack = msg_ack(hdr);
2194	u16 rcv_nxt = l->rcv_nxt;
2195	u16 rcvgap = 0;
2196	int mtyp = msg_type(hdr);
2197	int rc = 0, released;
2198	char *if_name;
2199	void *data;
2200
2201	trace_tipc_proto_rcv(skb, false, l->name);
2202
2203	if (dlen > U16_MAX)
2204		goto exit;
2205
2206	if (tipc_link_is_blocked(l) || !xmitq)
2207		goto exit;
2208
2209	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2210		l->net_plane = msg_net_plane(hdr);
2211
2212	if (skb_linearize(skb))
2213		goto exit;
2214
2215	hdr = buf_msg(skb);
2216	data = msg_data(hdr);
2217
2218	if (!tipc_link_validate_msg(l, hdr)) {
2219		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2220		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2221		goto exit;
2222	}
2223
2224	switch (mtyp) {
2225	case RESET_MSG:
2226	case ACTIVATE_MSG:
2227		msg_max = msg_max_pkt(hdr);
2228		if (msg_max < tipc_bearer_min_mtu(l->net, l->bearer_id))
2229			break;
2230		/* Complete own link name with peer's interface name */
2231		if_name =  strrchr(l->name, ':') + 1;
2232		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2233			break;
2234		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2235			break;
2236		strncpy(if_name, data, TIPC_MAX_IF_NAME);
2237
2238		/* Update own tolerance if peer indicates a non-zero value */
2239		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2240			l->tolerance = peers_tol;
2241			l->bc_rcvlink->tolerance = peers_tol;
2242		}
2243		/* Update own priority if peer's priority is higher */
2244		if (tipc_in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2245			l->priority = peers_prio;
2246
2247		/* If peer is going down we want full re-establish cycle */
2248		if (msg_peer_stopping(hdr)) {
2249			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2250			break;
2251		}
2252
2253		/* If this endpoint was re-created while peer was ESTABLISHING
2254		 * it doesn't know current session number. Force re-synch.
2255		 */
2256		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2257		    l->session != msg_dest_session(hdr)) {
2258			if (less(l->session, msg_dest_session(hdr)))
2259				l->session = msg_dest_session(hdr) + 1;
2260			break;
2261		}
2262
2263		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2264		if (mtyp == RESET_MSG || !link_is_up(l))
2265			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2266
2267		/* ACTIVATE_MSG takes up link if it was already locally reset */
2268		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2269			rc = TIPC_LINK_UP_EVT;
2270
2271		l->peer_session = msg_session(hdr);
2272		l->in_session = true;
2273		l->peer_bearer_id = msg_bearer_id(hdr);
2274		if (l->mtu > msg_max)
2275			l->mtu = msg_max;
2276		break;
2277
2278	case STATE_MSG:
2279		/* Validate Gap ACK blocks, drop if invalid */
2280		glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2281		if (glen > dlen)
2282			break;
2283
2284		l->rcv_nxt_state = msg_seqno(hdr) + 1;
2285
2286		/* Update own tolerance if peer indicates a non-zero value */
2287		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2288			l->tolerance = peers_tol;
2289			l->bc_rcvlink->tolerance = peers_tol;
2290		}
2291		/* Update own prio if peer indicates a different value */
2292		if ((peers_prio != l->priority) &&
2293		    tipc_in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2294			l->priority = peers_prio;
2295			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2296		}
2297
2298		l->silent_intv_cnt = 0;
2299		l->stats.recv_states++;
2300		if (msg_probe(hdr))
2301			l->stats.recv_probes++;
2302
2303		if (!link_is_up(l)) {
2304			if (l->state == LINK_ESTABLISHING)
2305				rc = TIPC_LINK_UP_EVT;
2306			break;
2307		}
2308
2309		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2310			     &l->mon_state, l->bearer_id);
2311
2312		/* Send NACK if peer has sent pkts we haven't received yet */
2313		if ((reply || msg_is_keepalive(hdr)) &&
2314		    more(peers_snd_nxt, rcv_nxt) &&
2315		    !tipc_link_is_synching(l) &&
2316		    skb_queue_empty(&l->deferdq))
2317			rcvgap = peers_snd_nxt - l->rcv_nxt;
2318		if (rcvgap || reply)
2319			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2320						  rcvgap, 0, 0, xmitq);
2321
2322		released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2323						     &retransmitted, &rc);
2324		if (gap)
2325			l->stats.recv_nacks++;
2326		if (released || retransmitted)
2327			tipc_link_update_cwin(l, released, retransmitted);
2328		if (released)
2329			tipc_link_advance_backlog(l, xmitq);
2330		if (unlikely(!skb_queue_empty(&l->wakeupq)))
2331			link_prepare_wakeup(l);
2332	}
2333exit:
2334	kfree_skb(skb);
2335	return rc;
2336}
2337
2338/* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2339 */
2340static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2341					 u16 peers_snd_nxt,
2342					 struct sk_buff_head *xmitq)
2343{
2344	struct sk_buff *skb;
2345	struct tipc_msg *hdr;
2346	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2347	u16 ack = l->rcv_nxt - 1;
2348	u16 gap_to = peers_snd_nxt - 1;
2349
2350	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2351			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2352	if (!skb)
2353		return false;
2354	hdr = buf_msg(skb);
2355	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2356	msg_set_bcast_ack(hdr, ack);
2357	msg_set_bcgap_after(hdr, ack);
2358	if (dfrd_skb)
2359		gap_to = buf_seqno(dfrd_skb) - 1;
2360	msg_set_bcgap_to(hdr, gap_to);
2361	msg_set_non_seq(hdr, bcast);
2362	__skb_queue_tail(xmitq, skb);
2363	return true;
2364}
2365
2366/* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2367 *
2368 * Give a newly added peer node the sequence number where it should
2369 * start receiving and acking broadcast packets.
2370 */
2371static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2372					struct sk_buff_head *xmitq)
2373{
2374	struct sk_buff_head list;
2375
2376	__skb_queue_head_init(&list);
2377	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2378		return;
2379	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2380	tipc_link_xmit(l, &list, xmitq);
2381}
2382
2383/* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2384 */
2385void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2386{
2387	int mtyp = msg_type(hdr);
2388	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2389
2390	if (link_is_up(l))
2391		return;
2392
2393	if (msg_user(hdr) == BCAST_PROTOCOL) {
2394		l->rcv_nxt = peers_snd_nxt;
2395		l->state = LINK_ESTABLISHED;
2396		return;
2397	}
2398
2399	if (l->peer_caps & TIPC_BCAST_SYNCH)
2400		return;
2401
2402	if (msg_peer_node_is_up(hdr))
2403		return;
2404
2405	/* Compatibility: accept older, less safe initial synch data */
2406	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2407		l->rcv_nxt = peers_snd_nxt;
2408}
2409
2410/* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2411 */
2412int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2413			  struct sk_buff_head *xmitq)
2414{
2415	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2416	int rc = 0;
2417
2418	if (!link_is_up(l))
2419		return rc;
2420
2421	if (!msg_peer_node_is_up(hdr))
2422		return rc;
2423
2424	/* Open when peer acknowledges our bcast init msg (pkt #1) */
2425	if (msg_ack(hdr))
2426		l->bc_peer_is_up = true;
2427
2428	if (!l->bc_peer_is_up)
2429		return rc;
2430
2431	/* Ignore if peers_snd_nxt goes beyond receive window */
2432	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2433		return rc;
2434
2435	l->snd_nxt = peers_snd_nxt;
2436	if (link_bc_rcv_gap(l))
2437		rc |= TIPC_LINK_SND_STATE;
2438
2439	/* Return now if sender supports nack via STATE messages */
2440	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2441		return rc;
2442
2443	/* Otherwise, be backwards compatible */
2444
2445	if (!more(peers_snd_nxt, l->rcv_nxt)) {
2446		l->nack_state = BC_NACK_SND_CONDITIONAL;
2447		return 0;
2448	}
2449
2450	/* Don't NACK if one was recently sent or peeked */
2451	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2452		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2453		return 0;
2454	}
2455
2456	/* Conditionally delay NACK sending until next synch rcv */
2457	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2458		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2459		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2460			return 0;
2461	}
2462
2463	/* Send NACK now but suppress next one */
2464	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2465	l->nack_state = BC_NACK_SND_SUPPRESS;
2466	return 0;
2467}
2468
2469int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2470			 struct tipc_gap_ack_blks *ga,
2471			 struct sk_buff_head *xmitq,
2472			 struct sk_buff_head *retrq)
2473{
2474	struct tipc_link *l = r->bc_sndlink;
2475	bool unused = false;
2476	int rc = 0;
2477
2478	if (!link_is_up(r) || !r->bc_peer_is_up)
2479		return 0;
2480
2481	if (gap) {
2482		l->stats.recv_nacks++;
2483		r->stats.recv_nacks++;
2484	}
2485
2486	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2487		return 0;
2488
2489	trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2490	tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2491
2492	tipc_link_advance_backlog(l, xmitq);
2493	if (unlikely(!skb_queue_empty(&l->wakeupq)))
2494		link_prepare_wakeup(l);
2495
2496	return rc;
2497}
2498
2499/* tipc_link_bc_nack_rcv(): receive broadcast nack message
2500 * This function is here for backwards compatibility, since
2501 * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2502 */
2503int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2504			  struct sk_buff_head *xmitq)
2505{
2506	struct tipc_msg *hdr = buf_msg(skb);
2507	u32 dnode = msg_destnode(hdr);
2508	int mtyp = msg_type(hdr);
2509	u16 acked = msg_bcast_ack(hdr);
2510	u16 from = acked + 1;
2511	u16 to = msg_bcgap_to(hdr);
2512	u16 peers_snd_nxt = to + 1;
2513	int rc = 0;
2514
2515	kfree_skb(skb);
2516
2517	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2518		return 0;
2519
2520	if (mtyp != STATE_MSG)
2521		return 0;
2522
2523	if (dnode == tipc_own_addr(l->net)) {
2524		rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2525					  xmitq);
2526		l->stats.recv_nacks++;
2527		return rc;
2528	}
2529
2530	/* Msg for other node => suppress own NACK at next sync if applicable */
2531	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2532		l->nack_state = BC_NACK_SND_SUPPRESS;
2533
2534	return 0;
2535}
2536
2537void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2538{
2539	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2540
2541	l->min_win = min_win;
2542	l->ssthresh = max_win;
2543	l->max_win = max_win;
2544	l->window = min_win;
2545	l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2546	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2547	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2548	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2549	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2550}
2551
2552/**
2553 * tipc_link_reset_stats - reset link statistics
2554 * @l: pointer to link
2555 */
2556void tipc_link_reset_stats(struct tipc_link *l)
2557{
2558	memset(&l->stats, 0, sizeof(l->stats));
2559}
2560
2561static void link_print(struct tipc_link *l, const char *str)
2562{
2563	struct sk_buff *hskb = skb_peek(&l->transmq);
2564	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2565	u16 tail = l->snd_nxt - 1;
2566
2567	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2568	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2569		skb_queue_len(&l->transmq), head, tail,
2570		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2571}
2572
2573/* Parse and validate nested (link) properties valid for media, bearer and link
2574 */
2575int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2576{
2577	int err;
2578
2579	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2580					  tipc_nl_prop_policy, NULL);
2581	if (err)
2582		return err;
2583
2584	if (props[TIPC_NLA_PROP_PRIO]) {
2585		u32 prio;
2586
2587		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2588		if (prio > TIPC_MAX_LINK_PRI)
2589			return -EINVAL;
2590	}
2591
2592	if (props[TIPC_NLA_PROP_TOL]) {
2593		u32 tol;
2594
2595		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2596		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2597			return -EINVAL;
2598	}
2599
2600	if (props[TIPC_NLA_PROP_WIN]) {
2601		u32 max_win;
2602
2603		max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2604		if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2605			return -EINVAL;
2606	}
2607
2608	return 0;
2609}
2610
2611static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2612{
2613	int i;
2614	struct nlattr *stats;
2615
2616	struct nla_map {
2617		u32 key;
2618		u32 val;
2619	};
2620
2621	struct nla_map map[] = {
2622		{TIPC_NLA_STATS_RX_INFO, 0},
2623		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2624		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2625		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2626		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2627		{TIPC_NLA_STATS_TX_INFO, 0},
2628		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2629		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2630		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2631		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2632		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2633			s->msg_length_counts : 1},
2634		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2635		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2636		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2637		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2638		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2639		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2640		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2641		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2642		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2643		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2644		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2645		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2646		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2647		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2648		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2649		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2650		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2651		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2652		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2653		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2654		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2655		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2656			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2657	};
2658
2659	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2660	if (!stats)
2661		return -EMSGSIZE;
2662
2663	for (i = 0; i <  ARRAY_SIZE(map); i++)
2664		if (nla_put_u32(skb, map[i].key, map[i].val))
2665			goto msg_full;
2666
2667	nla_nest_end(skb, stats);
2668
2669	return 0;
2670msg_full:
2671	nla_nest_cancel(skb, stats);
2672
2673	return -EMSGSIZE;
2674}
2675
2676/* Caller should hold appropriate locks to protect the link */
2677int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2678		       struct tipc_link *link, int nlflags)
2679{
2680	u32 self = tipc_own_addr(net);
2681	struct nlattr *attrs;
2682	struct nlattr *prop;
2683	void *hdr;
2684	int err;
2685
2686	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2687			  nlflags, TIPC_NL_LINK_GET);
2688	if (!hdr)
2689		return -EMSGSIZE;
2690
2691	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2692	if (!attrs)
2693		goto msg_full;
2694
2695	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2696		goto attr_msg_full;
2697	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2698		goto attr_msg_full;
2699	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2700		goto attr_msg_full;
2701	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2702		goto attr_msg_full;
2703	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2704		goto attr_msg_full;
2705
2706	if (tipc_link_is_up(link))
2707		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2708			goto attr_msg_full;
2709	if (link->active)
2710		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2711			goto attr_msg_full;
2712
2713	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2714	if (!prop)
2715		goto attr_msg_full;
2716	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2717		goto prop_msg_full;
2718	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2719		goto prop_msg_full;
2720	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2721			link->window))
2722		goto prop_msg_full;
2723	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2724		goto prop_msg_full;
2725	nla_nest_end(msg->skb, prop);
2726
2727	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2728	if (err)
2729		goto attr_msg_full;
2730
2731	nla_nest_end(msg->skb, attrs);
2732	genlmsg_end(msg->skb, hdr);
2733
2734	return 0;
2735
2736prop_msg_full:
2737	nla_nest_cancel(msg->skb, prop);
2738attr_msg_full:
2739	nla_nest_cancel(msg->skb, attrs);
2740msg_full:
2741	genlmsg_cancel(msg->skb, hdr);
2742
2743	return -EMSGSIZE;
2744}
2745
2746static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2747				      struct tipc_stats *stats)
2748{
2749	int i;
2750	struct nlattr *nest;
2751
2752	struct nla_map {
2753		__u32 key;
2754		__u32 val;
2755	};
2756
2757	struct nla_map map[] = {
2758		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2759		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2760		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2761		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2762		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2763		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2764		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2765		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2766		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2767		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2768		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2769		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2770		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2771		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2772		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2773		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2774		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2775		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2776		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2777			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2778	};
2779
2780	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2781	if (!nest)
2782		return -EMSGSIZE;
2783
2784	for (i = 0; i <  ARRAY_SIZE(map); i++)
2785		if (nla_put_u32(skb, map[i].key, map[i].val))
2786			goto msg_full;
2787
2788	nla_nest_end(skb, nest);
2789
2790	return 0;
2791msg_full:
2792	nla_nest_cancel(skb, nest);
2793
2794	return -EMSGSIZE;
2795}
2796
2797int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2798			struct tipc_link *bcl)
2799{
2800	int err;
2801	void *hdr;
2802	struct nlattr *attrs;
2803	struct nlattr *prop;
2804	u32 bc_mode = tipc_bcast_get_mode(net);
2805	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2806
2807	if (!bcl)
2808		return 0;
2809
2810	tipc_bcast_lock(net);
2811
2812	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2813			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2814	if (!hdr) {
2815		tipc_bcast_unlock(net);
2816		return -EMSGSIZE;
2817	}
2818
2819	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2820	if (!attrs)
2821		goto msg_full;
2822
2823	/* The broadcast link is always up */
2824	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2825		goto attr_msg_full;
2826
2827	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2828		goto attr_msg_full;
2829	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2830		goto attr_msg_full;
2831	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2832		goto attr_msg_full;
2833	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2834		goto attr_msg_full;
2835
2836	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2837	if (!prop)
2838		goto attr_msg_full;
2839	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2840		goto prop_msg_full;
2841	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2842		goto prop_msg_full;
2843	if (bc_mode & BCLINK_MODE_SEL)
2844		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2845				bc_ratio))
2846			goto prop_msg_full;
2847	nla_nest_end(msg->skb, prop);
2848
2849	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2850	if (err)
2851		goto attr_msg_full;
2852
2853	tipc_bcast_unlock(net);
2854	nla_nest_end(msg->skb, attrs);
2855	genlmsg_end(msg->skb, hdr);
2856
2857	return 0;
2858
2859prop_msg_full:
2860	nla_nest_cancel(msg->skb, prop);
2861attr_msg_full:
2862	nla_nest_cancel(msg->skb, attrs);
2863msg_full:
2864	tipc_bcast_unlock(net);
2865	genlmsg_cancel(msg->skb, hdr);
2866
2867	return -EMSGSIZE;
2868}
2869
2870void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2871			     struct sk_buff_head *xmitq)
2872{
2873	l->tolerance = tol;
2874	if (l->bc_rcvlink)
2875		l->bc_rcvlink->tolerance = tol;
2876	if (link_is_up(l))
2877		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2878}
2879
2880void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2881			struct sk_buff_head *xmitq)
2882{
2883	l->priority = prio;
2884	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2885}
2886
2887void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2888{
2889	l->abort_limit = limit;
2890}
2891
2892/**
2893 * tipc_link_dump - dump TIPC link data
2894 * @l: tipc link to be dumped
2895 * @dqueues: bitmask to decide if any link queue to be dumped?
2896 *           - TIPC_DUMP_NONE: don't dump link queues
2897 *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2898 *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2899 *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2900 *           - TIPC_DUMP_INPUTQ: dump link input queue
2901 *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2902 *           - TIPC_DUMP_ALL: dump all the link queues above
2903 * @buf: returned buffer of dump data in format
2904 */
2905int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2906{
2907	int i = 0;
2908	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2909	struct sk_buff_head *list;
2910	struct sk_buff *hskb, *tskb;
2911	u32 len;
2912
2913	if (!l) {
2914		i += scnprintf(buf, sz, "link data: (null)\n");
2915		return i;
2916	}
2917
2918	i += scnprintf(buf, sz, "link data: %x", l->addr);
2919	i += scnprintf(buf + i, sz - i, " %x", l->state);
2920	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2921	i += scnprintf(buf + i, sz - i, " %u", l->session);
2922	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2923	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2924	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2925	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2926	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2927	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2928	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2929	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2930	i += scnprintf(buf + i, sz - i, " %u", 0);
2931	i += scnprintf(buf + i, sz - i, " %u", 0);
2932	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2933
2934	list = &l->transmq;
2935	len = skb_queue_len(list);
2936	hskb = skb_peek(list);
2937	tskb = skb_peek_tail(list);
2938	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2939		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2940		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2941
2942	list = &l->deferdq;
2943	len = skb_queue_len(list);
2944	hskb = skb_peek(list);
2945	tskb = skb_peek_tail(list);
2946	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2947		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2948		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2949
2950	list = &l->backlogq;
2951	len = skb_queue_len(list);
2952	hskb = skb_peek(list);
2953	tskb = skb_peek_tail(list);
2954	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2955		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2956		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2957
2958	list = l->inputq;
2959	len = skb_queue_len(list);
2960	hskb = skb_peek(list);
2961	tskb = skb_peek_tail(list);
2962	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2963		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2964		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2965
2966	if (dqueues & TIPC_DUMP_TRANSMQ) {
2967		i += scnprintf(buf + i, sz - i, "transmq: ");
2968		i += tipc_list_dump(&l->transmq, false, buf + i);
2969	}
2970	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2971		i += scnprintf(buf + i, sz - i,
2972			       "backlogq: <%u %u %u %u %u>, ",
2973			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2974			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2975			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2976			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2977			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2978		i += tipc_list_dump(&l->backlogq, false, buf + i);
2979	}
2980	if (dqueues & TIPC_DUMP_DEFERDQ) {
2981		i += scnprintf(buf + i, sz - i, "deferdq: ");
2982		i += tipc_list_dump(&l->deferdq, false, buf + i);
2983	}
2984	if (dqueues & TIPC_DUMP_INPUTQ) {
2985		i += scnprintf(buf + i, sz - i, "inputq: ");
2986		i += tipc_list_dump(l->inputq, false, buf + i);
2987	}
2988	if (dqueues & TIPC_DUMP_WAKEUP) {
2989		i += scnprintf(buf + i, sz - i, "wakeup: ");
2990		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2991	}
2992
2993	return i;
2994}